Vulnerability-Lookup

BDU:2026-14928 (CVE-2026-81000)

Vulnerability from fstec – Published: 2026-09-19 – Updated: 2026-09-20 – View on bdu.fstec.ru Exploit publicly available Fixed

Title

Уязвимость функции tun_get_user() виртуального сетевого драйвера TUN ядра операционной системы Linux, позволяющая нарушителю повысить свои привилегии

Summary

Уязвимость функции tun_get_user() виртуального сетевого драйвера TUN ядра операционной системы Linux связана с записью за границами буфера. Эксплуатация уязвимости может позволить нарушителю повысить свои привилегии

Severity

6.8 (Medium) CVSS 2.0


                      
                        AV:L/AC:L/Au:S/C:C/I:C/A:C

7.8 (High) CVSS 3.1


                      
                        CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Class

Code vulnerability

Status

Confirmed by the vendor

Exploitation

Data structure manipulation

Incidents

Being clarified

Remediation

Software update

CWE

CWE-787 - Запись за границами буфера

Aliases

CVE-2026-81000

References

11 references

URL
https://git.kernel.org/stable/c/010eee265d6bd8769b6a523d2a0693d9b3f5df43
https://git.kernel.org/stable/c/0ada54ea63e48b9c1608e917ccb7dfadbe86db28
https://git.kernel.org/stable/c/18ef24cdb2eba32e38f1d27f2d02b7b4212e8f76
https://git.kernel.org/stable/c/379d85c7f25f3e05a428225e6b8a65613c6e9b9d
https://git.kernel.org/stable/c/447c9303942c439a117d9b76ce6d6e2116b38ee7
https://git.kernel.org/stable/c/708e87937de93f445225c134a2e20519f9b4ce60
https://git.kernel.org/stable/c/ad715e713610d2d5473c3a6498c825ccecf26491
https://git.kernel.org/stable/c/e098d9cc8859614a7f7baebc96e32a5a16b18ed2
https://access.redhat.com/security/cve/cve-2026-81000
https://ubuntu.com/security/CVE-2026-81000
https://github.com/manizada/TUNderflow

Impacted products

4 products from 4 vendors

Vendors

Red Hat, Inc., Canonical Ltd., Сообщество свободного программного обеспечения

Products

Red Hat Enterprise Linux, Ubuntu, Red Hat OpenShift Container Platform, Linux

Versions

7 (Red Hat Enterprise Linux), 16.04 LTS (Ubuntu), 18.04 LTS (Ubuntu), 8 (Red Hat Enterprise Linux), 20.04 LTS (Ubuntu), 4 (Red Hat OpenShift Container Platform), 22.04 LTS (Ubuntu), 9 (Red Hat Enterprise Linux), 24.04 LTS (Ubuntu), 10 (Red Hat Enterprise Linux), 26.04 LTS (Ubuntu), до 7.3 rc1 (Linux), от 4.6.0 до 6.12.109 (Linux), от 6.18.0 до 6.18.50 (Linux), от 7.2.0 до 7.2.4 (Linux)

Product types

Operating system, Application software

Platforms

Red Hat, Inc. Red Hat Enterprise Linux 7, Canonical Ltd. Ubuntu 16.04 LTS, Canonical Ltd. Ubuntu 18.04 LTS, Inc. Red Hat Enterprise Linux 8, Canonical Ltd. Ubuntu 20.04 LTS, Canonical Ltd. Ubuntu 22.04 LTS, Inc. Red Hat Enterprise Linux 9, Canonical Ltd. Ubuntu 24.04 LTS, Inc. Red Hat Enterprise Linux 10, Canonical Ltd. Ubuntu 26.04 LTS, Сообщество свободного программного обеспечения Linux до 7.3 rc1, Сообщество свободного программного обеспечения Linux от 4.6.0 до 6.12.109, Сообщество свободного программного обеспечения Linux от 6.18.0 до 6.18.50, Сообщество свободного программного обеспечения Linux от 7.2.0 до 7.2.4

Mitigations

Credits

Уязвимость получила название TUNderflow

JSON

To clipboard

{
  "CVSS 2.0": "AV:L/AC:L/Au:S/C:C/I:C/A:C",
  "CVSS 3.0": "AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
  "CVSS 4.0": null,
  "remediation_\u0418\u0434\u0435\u043d\u0442\u0438\u0444\u0438\u043a\u0430\u0442\u043e\u0440": null,
  "remediation_\u041d\u0430\u0438\u043c\u0435\u043d\u043e\u0432\u0430\u043d\u0438\u0435": null,
  "\u0412\u0435\u043d\u0434\u043e\u0440 \u041f\u041e": "Red Hat, Inc., Canonical Ltd., \u0421\u043e\u043e\u0431\u0449\u0435\u0441\u0442\u0432\u043e \u0441\u0432\u043e\u0431\u043e\u0434\u043d\u043e\u0433\u043e \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u043e\u0433\u043e \u043e\u0431\u0435\u0441\u043f\u0435\u0447\u0435\u043d\u0438\u044f",
  "\u0412\u0435\u0440\u0441\u0438\u044f \u041f\u041e": "7 (Red Hat Enterprise Linux), 16.04 LTS (Ubuntu), 18.04 LTS (Ubuntu), 8 (Red Hat Enterprise Linux), 20.04 LTS (Ubuntu), 4 (Red Hat OpenShift Container Platform), 22.04 LTS (Ubuntu), 9 (Red Hat Enterprise Linux), 24.04 LTS (Ubuntu), 10 (Red Hat Enterprise Linux), 26.04 LTS (Ubuntu), \u0434\u043e 7.3 rc1 (Linux), \u043e\u0442 4.6.0 \u0434\u043e 6.12.109 (Linux), \u043e\u0442 6.18.0 \u0434\u043e 6.18.50 (Linux), \u043e\u0442 7.2.0 \u0434\u043e 7.2.4 (Linux)",
  "\u0412\u043e\u0437\u043c\u043e\u0436\u043d\u044b\u0435 \u043c\u0435\u0440\u044b \u043f\u043e \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0438\u044e": "\u0412 \u0443\u0441\u043b\u043e\u0432\u0438\u044f\u0445 \u043e\u0442\u0441\u0443\u0442\u0441\u0442\u0432\u0438\u044f \u043e\u0431\u043d\u043e\u0432\u043b\u0435\u043d\u0438\u0439 \u0431\u0435\u0437\u043e\u043f\u0430\u0441\u043d\u043e\u0441\u0442\u0438 \u043e\u0442 \u043f\u0440\u043e\u0438\u0437\u0432\u043e\u0434\u0438\u0442\u0435\u043b\u044f \u0440\u0435\u043a\u043e\u043c\u0435\u043d\u0434\u0443\u0435\u0442\u0441\u044f \u043f\u0440\u0438\u0434\u0435\u0440\u0436\u0438\u0432\u0430\u0442\u044c\u0441\u044f \"\u0420\u0435\u043a\u043e\u043c\u0435\u043d\u0434\u0430\u0446\u0438\u0439 \u043f\u043e \u0431\u0435\u0437\u043e\u043f\u0430\u0441\u043d\u043e\u0439 \u043d\u0430\u0441\u0442\u0440\u043e\u0439\u043a\u0435 \u043e\u043f\u0435\u0440\u0430\u0446\u0438\u043e\u043d\u043d\u044b\u0445 \u0441\u0438\u0441\u0442\u0435\u043c LINUX\", \u0438\u0437\u043b\u043e\u0436\u0435\u043d\u043d\u044b\u0445 \u0432 \u043c\u0435\u0442\u043e\u0434\u0438\u0447\u0435\u0441\u043a\u043e\u043c \u0434\u043e\u043a\u0443\u043c\u0435\u043d\u0442\u0435 \u0424\u0421\u0422\u042d\u041a \u0420\u043e\u0441\u0441\u0438\u0438, \u0443\u0442\u0432\u0435\u0440\u0436\u0434\u0451\u043d\u043d\u043e\u043c 25 \u0434\u0435\u043a\u0430\u0431\u0440\u044f 2022 \u0433\u043e\u0434\u0430.\n\n\u0418\u0441\u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u043d\u0438\u0435 \u0440\u0435\u043a\u043e\u043c\u0435\u043d\u0434\u0430\u0446\u0438\u0439:\n\u0414\u043b\u044f Linux:\nhttps://git.kernel.org/stable/c/010eee265d6bd8769b6a523d2a0693d9b3f5df43\nhttps://git.kernel.org/stable/c/0ada54ea63e48b9c1608e917ccb7dfadbe86db28\nhttps://git.kernel.org/stable/c/18ef24cdb2eba32e38f1d27f2d02b7b4212e8f76\nhttps://git.kernel.org/stable/c/379d85c7f25f3e05a428225e6b8a65613c6e9b9d\nhttps://git.kernel.org/stable/c/447c9303942c439a117d9b76ce6d6e2116b38ee7\nhttps://git.kernel.org/stable/c/708e87937de93f445225c134a2e20519f9b4ce60\nhttps://git.kernel.org/stable/c/ad715e713610d2d5473c3a6498c825ccecf26491\nhttps://git.kernel.org/stable/c/e098d9cc8859614a7f7baebc96e32a5a16b18ed2\n\n\u0414\u043b\u044f \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u044b\u0445 \u043f\u0440\u043e\u0434\u0443\u043a\u0442\u043e\u0432 Red Hat Inc.:\nhttps://access.redhat.com/security/cve/cve-2026-81000\n\n\u0414\u043b\u044f \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u044b\u0445 \u043f\u0440\u043e\u0434\u0443\u043a\u0442\u043e\u0432 Ubuntu:\nhttps://ubuntu.com/security/CVE-2026-81000",
  "\u0414\u0430\u0442\u0430 \u0432\u044b\u044f\u0432\u043b\u0435\u043d\u0438\u044f": "12.08.2026",
  "\u0414\u0430\u0442\u0430 \u043f\u043e\u0441\u043b\u0435\u0434\u043d\u0435\u0433\u043e \u043e\u0431\u043d\u043e\u0432\u043b\u0435\u043d\u0438\u044f": "20.09.2026",
  "\u0414\u0430\u0442\u0430 \u043f\u0443\u0431\u043b\u0438\u043a\u0430\u0446\u0438\u0438": "19.09.2026",
  "\u0418\u0434\u0435\u043d\u0442\u0438\u0444\u0438\u043a\u0430\u0442\u043e\u0440": "BDU:2026-14928",
  "\u0418\u0434\u0435\u043d\u0442\u0438\u0444\u0438\u043a\u0430\u0442\u043e\u0440\u044b \u0434\u0440\u0443\u0433\u0438\u0445 \u0441\u0438\u0441\u0442\u0435\u043c \u043e\u043f\u0438\u0441\u0430\u043d\u0438\u0439 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "CVE-2026-81000",
  "\u0418\u043d\u0444\u043e\u0440\u043c\u0430\u0446\u0438\u044f \u043e\u0431 \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0438\u0438": "\u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0430",
  "\u041a\u043b\u0430\u0441\u0441 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u043a\u043e\u0434\u0430",
  "\u041d\u0430\u0437\u0432\u0430\u043d\u0438\u0435 \u041f\u041e": "Red Hat Enterprise Linux, Ubuntu, Red Hat OpenShift Container Platform, Linux",
  "\u041d\u0430\u0438\u043c\u0435\u043d\u043e\u0432\u0430\u043d\u0438\u0435 \u041e\u0421 \u0438 \u0442\u0438\u043f \u0430\u043f\u043f\u0430\u0440\u0430\u0442\u043d\u043e\u0439 \u043f\u043b\u0430\u0442\u0444\u043e\u0440\u043c\u044b": "Red Hat, Inc. Red Hat Enterprise Linux 7 , Canonical Ltd. Ubuntu 16.04 LTS , Canonical Ltd. Ubuntu 18.04 LTS , Red Hat, Inc. Red Hat Enterprise Linux 8 , Canonical Ltd. Ubuntu 20.04 LTS , Canonical Ltd. Ubuntu 22.04 LTS , Red Hat, Inc. Red Hat Enterprise Linux 9 , Canonical Ltd. Ubuntu 24.04 LTS , Red Hat, Inc. Red Hat Enterprise Linux 10 , Canonical Ltd. Ubuntu 26.04 LTS , \u0421\u043e\u043e\u0431\u0449\u0435\u0441\u0442\u0432\u043e \u0441\u0432\u043e\u0431\u043e\u0434\u043d\u043e\u0433\u043e \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u043e\u0433\u043e \u043e\u0431\u0435\u0441\u043f\u0435\u0447\u0435\u043d\u0438\u044f Linux \u0434\u043e 7.3 rc1 , \u0421\u043e\u043e\u0431\u0449\u0435\u0441\u0442\u0432\u043e \u0441\u0432\u043e\u0431\u043e\u0434\u043d\u043e\u0433\u043e \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u043e\u0433\u043e \u043e\u0431\u0435\u0441\u043f\u0435\u0447\u0435\u043d\u0438\u044f Linux \u043e\u0442 4.6.0 \u0434\u043e 6.12.109 , \u0421\u043e\u043e\u0431\u0449\u0435\u0441\u0442\u0432\u043e \u0441\u0432\u043e\u0431\u043e\u0434\u043d\u043e\u0433\u043e \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u043e\u0433\u043e \u043e\u0431\u0435\u0441\u043f\u0435\u0447\u0435\u043d\u0438\u044f Linux \u043e\u0442 6.18.0 \u0434\u043e 6.18.50 , \u0421\u043e\u043e\u0431\u0449\u0435\u0441\u0442\u0432\u043e \u0441\u0432\u043e\u0431\u043e\u0434\u043d\u043e\u0433\u043e \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u043e\u0433\u043e \u043e\u0431\u0435\u0441\u043f\u0435\u0447\u0435\u043d\u0438\u044f Linux \u043e\u0442 7.2.0 \u0434\u043e 7.2.4 ",
  "\u041d\u0430\u0438\u043c\u0435\u043d\u043e\u0432\u0430\u043d\u0438\u0435 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u0444\u0443\u043d\u043a\u0446\u0438\u0438 tun_get_user() \u0432\u0438\u0440\u0442\u0443\u0430\u043b\u044c\u043d\u043e\u0433\u043e \u0441\u0435\u0442\u0435\u0432\u043e\u0433\u043e \u0434\u0440\u0430\u0439\u0432\u0435\u0440\u0430 TUN \u044f\u0434\u0440\u0430 \u043e\u043f\u0435\u0440\u0430\u0446\u0438\u043e\u043d\u043d\u043e\u0439 \u0441\u0438\u0441\u0442\u0435\u043c\u044b Linux, \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0430\u044f \u043d\u0430\u0440\u0443\u0448\u0438\u0442\u0435\u043b\u044e \u043f\u043e\u0432\u044b\u0441\u0438\u0442\u044c \u0441\u0432\u043e\u0438 \u043f\u0440\u0438\u0432\u0438\u043b\u0435\u0433\u0438\u0438",
  "\u041d\u0430\u043b\u0438\u0447\u0438\u0435 \u044d\u043a\u0441\u043f\u043b\u043e\u0439\u0442\u0430": "\u0421\u0443\u0449\u0435\u0441\u0442\u0432\u0443\u0435\u0442 \u0432 \u043e\u0442\u043a\u0440\u044b\u0442\u043e\u043c \u0434\u043e\u0441\u0442\u0443\u043f\u0435",
  "\u041e\u043f\u0438\u0441\u0430\u043d\u0438\u0435 \u043e\u0448\u0438\u0431\u043a\u0438 CWE": "\u0417\u0430\u043f\u0438\u0441\u044c \u0437\u0430 \u0433\u0440\u0430\u043d\u0438\u0446\u0430\u043c\u0438 \u0431\u0443\u0444\u0435\u0440\u0430 (CWE-787)",
  "\u041e\u043f\u0438\u0441\u0430\u043d\u0438\u0435 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u0444\u0443\u043d\u043a\u0446\u0438\u0438 tun_get_user() \u0432\u0438\u0440\u0442\u0443\u0430\u043b\u044c\u043d\u043e\u0433\u043e \u0441\u0435\u0442\u0435\u0432\u043e\u0433\u043e \u0434\u0440\u0430\u0439\u0432\u0435\u0440\u0430 TUN \u044f\u0434\u0440\u0430 \u043e\u043f\u0435\u0440\u0430\u0446\u0438\u043e\u043d\u043d\u043e\u0439 \u0441\u0438\u0441\u0442\u0435\u043c\u044b Linux \u0441\u0432\u044f\u0437\u0430\u043d\u0430 \u0441 \u0437\u0430\u043f\u0438\u0441\u044c\u044e \u0437\u0430 \u0433\u0440\u0430\u043d\u0438\u0446\u0430\u043c\u0438 \u0431\u0443\u0444\u0435\u0440\u0430. \u042d\u043a\u0441\u043f\u043b\u0443\u0430\u0442\u0430\u0446\u0438\u044f \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438 \u043c\u043e\u0436\u0435\u0442 \u043f\u043e\u0437\u0432\u043e\u043b\u0438\u0442\u044c \u043d\u0430\u0440\u0443\u0448\u0438\u0442\u0435\u043b\u044e \u043f\u043e\u0432\u044b\u0441\u0438\u0442\u044c \u0441\u0432\u043e\u0438 \u043f\u0440\u0438\u0432\u0438\u043b\u0435\u0433\u0438\u0438",
  "\u041f\u043e\u0441\u043b\u0435\u0434\u0441\u0442\u0432\u0438\u044f \u044d\u043a\u0441\u043f\u043b\u0443\u0430\u0442\u0430\u0446\u0438\u0438 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": null,
  "\u041f\u0440\u043e\u0447\u0430\u044f \u0438\u043d\u0444\u043e\u0440\u043c\u0430\u0446\u0438\u044f": "\u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u043f\u043e\u043b\u0443\u0447\u0438\u043b\u0430 \u043d\u0430\u0437\u0432\u0430\u043d\u0438\u0435 TUNderflow",
  "\u0421\u0432\u044f\u0437\u044c \u0441 \u0438\u043d\u0446\u0438\u0434\u0435\u043d\u0442\u0430\u043c\u0438 \u0418\u0411": "\u0414\u0430\u043d\u043d\u044b\u0435 \u0443\u0442\u043e\u0447\u043d\u044f\u044e\u0442\u0441\u044f",
  "\u0421\u043e\u0441\u0442\u043e\u044f\u043d\u0438\u0435 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u041e\u043f\u0443\u0431\u043b\u0438\u043a\u043e\u0432\u0430\u043d\u0430",
  "\u0421\u043f\u043e\u0441\u043e\u0431 \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0438\u044f": "\u041e\u0431\u043d\u043e\u0432\u043b\u0435\u043d\u0438\u0435 \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u043e\u0433\u043e \u043e\u0431\u0435\u0441\u043f\u0435\u0447\u0435\u043d\u0438\u044f",
  "\u0421\u043f\u043e\u0441\u043e\u0431 \u044d\u043a\u0441\u043f\u043b\u0443\u0430\u0442\u0430\u0446\u0438\u0438": "\u041c\u0430\u043d\u0438\u043f\u0443\u043b\u0438\u0440\u043e\u0432\u0430\u043d\u0438\u0435 \u0441\u0442\u0440\u0443\u043a\u0442\u0443\u0440\u0430\u043c\u0438 \u0434\u0430\u043d\u043d\u044b\u0445",
  "\u0421\u0441\u044b\u043b\u043a\u0438 \u043d\u0430 \u0438\u0441\u0442\u043e\u0447\u043d\u0438\u043a\u0438": "https://git.kernel.org/stable/c/010eee265d6bd8769b6a523d2a0693d9b3f5df43\nhttps://git.kernel.org/stable/c/0ada54ea63e48b9c1608e917ccb7dfadbe86db28\nhttps://git.kernel.org/stable/c/18ef24cdb2eba32e38f1d27f2d02b7b4212e8f76\nhttps://git.kernel.org/stable/c/379d85c7f25f3e05a428225e6b8a65613c6e9b9d\nhttps://git.kernel.org/stable/c/447c9303942c439a117d9b76ce6d6e2116b38ee7\nhttps://git.kernel.org/stable/c/708e87937de93f445225c134a2e20519f9b4ce60\nhttps://git.kernel.org/stable/c/ad715e713610d2d5473c3a6498c825ccecf26491\nhttps://git.kernel.org/stable/c/e098d9cc8859614a7f7baebc96e32a5a16b18ed2\nhttps://access.redhat.com/security/cve/cve-2026-81000\nhttps://ubuntu.com/security/CVE-2026-81000\nhttps://github.com/manizada/TUNderflow",
  "\u0421\u0442\u0430\u0442\u0443\u0441 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u041f\u043e\u0434\u0442\u0432\u0435\u0440\u0436\u0434\u0435\u043d\u0430 \u043f\u0440\u043e\u0438\u0437\u0432\u043e\u0434\u0438\u0442\u0435\u043b\u0435\u043c",
  "\u0422\u0438\u043f \u041f\u041e": "\u041e\u043f\u0435\u0440\u0430\u0446\u0438\u043e\u043d\u043d\u0430\u044f \u0441\u0438\u0441\u0442\u0435\u043c\u0430, \u041f\u0440\u0438\u043a\u043b\u0430\u0434\u043d\u043e\u0435 \u041f\u041e \u0438\u043d\u0444\u043e\u0440\u043c\u0430\u0446\u0438\u043e\u043d\u043d\u044b\u0445 \u0441\u0438\u0441\u0442\u0435\u043c",
  "\u0422\u0438\u043f \u043e\u0448\u0438\u0431\u043a\u0438 CWE": "CWE-787",
  "\u0423\u0440\u043e\u0432\u0435\u043d\u044c \u043e\u043f\u0430\u0441\u043d\u043e\u0441\u0442\u0438 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u0421\u0440\u0435\u0434\u043d\u0438\u0439 \u0443\u0440\u043e\u0432\u0435\u043d\u044c \u043e\u043f\u0430\u0441\u043d\u043e\u0441\u0442\u0438 (\u0431\u0430\u0437\u043e\u0432\u0430\u044f \u043e\u0446\u0435\u043d\u043a\u0430 CVSS 2.0 \u0441\u043e\u0441\u0442\u0430\u0432\u043b\u044f\u0435\u0442 6,8)\n\u0412\u044b\u0441\u043e\u043a\u0438\u0439 \u0443\u0440\u043e\u0432\u0435\u043d\u044c \u043e\u043f\u0430\u0441\u043d\u043e\u0441\u0442\u0438 (\u0431\u0430\u0437\u043e\u0432\u0430\u044f \u043e\u0446\u0435\u043d\u043a\u0430 CVSS 3.1 \u0441\u043e\u0441\u0442\u0430\u0432\u043b\u044f\u0435\u0442 7,8)"
}

CVE-2026-81000 (GCVE-0-2026-81000)

Vulnerability from cvelistv5 – Published: 2026-09-11 19:42 – Updated: 2026-09-14 11:59

Title

net: tun: bound receive headroom

Summary

In the Linux kernel, the following vulnerability has been resolved: net: tun: bound receive headroom tun_get_user() uses tun->align both as skb headroom and when choosing how much packet data to keep linear. OVS can propagate an oversized headroom request from another port to TUN or TAP. When align is larger than the usable space in a one-page skb head, SKB_MAX_HEAD(align) underflows and the result becomes negative when stored in good_linear. That value later wraps when assigned to the size_t linear variable, and tun_alloc_skb() can place skb->data outside the allocated head. Bound the headroom stored by TUN to the one-page skb-head budget and the largest non-sentinel 16-bit skb header offset. Leave one linear byte for raw TUN and a complete Ethernet header for TAP, including NET_IP_ALIGN. Also pull the raw-TUN protocol byte and the TAP Ethernet header before accessing them, so these checks remain safe for nonlinear skbs supplied by other allocation paths.

Severity

7.8 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Assigner

Linux mitre root

References

8 references

URL	Tags
https://git.kernel.org/stable/c/ad715e713610d2d54…
https://git.kernel.org/stable/c/708e87937de93f445…
https://git.kernel.org/stable/c/18ef24cdb2eba32e3…
https://git.kernel.org/stable/c/010eee265d6bd8769…
https://git.kernel.org/stable/c/379d85c7f25f3e05a…
https://git.kernel.org/stable/c/e098d9cc8859614a7…
https://git.kernel.org/stable/c/0ada54ea63e48b9c1…
https://git.kernel.org/stable/c/447c9303942c439a1…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: eaea34b23c46bf17b4a5638be69ab3561854f34b , < ad715e713610d2d5473c3a6498c825ccecf26491 (git) Affected: eaea34b23c46bf17b4a5638be69ab3561854f34b , < 708e87937de93f445225c134a2e20519f9b4ce60 (git) Affected: eaea34b23c46bf17b4a5638be69ab3561854f34b , < 18ef24cdb2eba32e38f1d27f2d02b7b4212e8f76 (git) Affected: eaea34b23c46bf17b4a5638be69ab3561854f34b , < 010eee265d6bd8769b6a523d2a0693d9b3f5df43 (git) Affected: eaea34b23c46bf17b4a5638be69ab3561854f34b , < 379d85c7f25f3e05a428225e6b8a65613c6e9b9d (git) Affected: eaea34b23c46bf17b4a5638be69ab3561854f34b , < e098d9cc8859614a7f7baebc96e32a5a16b18ed2 (git) Affected: eaea34b23c46bf17b4a5638be69ab3561854f34b , < 0ada54ea63e48b9c1608e917ccb7dfadbe86db28 (git) Affected: eaea34b23c46bf17b4a5638be69ab3561854f34b , < 447c9303942c439a117d9b76ce6d6e2116b38ee7 (git)
Linux	Linux	Affected: 4.6 Unaffected: 0 , < 4.6 (semver) Unaffected: 5.10.270 , ≤ 5.10.* (semver) Unaffected: 5.15.221 , ≤ 5.15.* (semver) Unaffected: 6.1.188 , ≤ 6.1.* (semver) Unaffected: 6.6.157 , ≤ 6.6.* (semver) Unaffected: 6.12.109 , ≤ 6.12.* (semver) Unaffected: 6.18.50 , ≤ 6.18.* (semver) Unaffected: 7.2.4 , ≤ 7.2.* (semver) Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)

Show details on NVD website

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/tun.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "ad715e713610d2d5473c3a6498c825ccecf26491",
              "status": "affected",
              "version": "eaea34b23c46bf17b4a5638be69ab3561854f34b",
              "versionType": "git"
            },
            {
              "lessThan": "708e87937de93f445225c134a2e20519f9b4ce60",
              "status": "affected",
              "version": "eaea34b23c46bf17b4a5638be69ab3561854f34b",
              "versionType": "git"
            },
            {
              "lessThan": "18ef24cdb2eba32e38f1d27f2d02b7b4212e8f76",
              "status": "affected",
              "version": "eaea34b23c46bf17b4a5638be69ab3561854f34b",
              "versionType": "git"
            },
            {
              "lessThan": "010eee265d6bd8769b6a523d2a0693d9b3f5df43",
              "status": "affected",
              "version": "eaea34b23c46bf17b4a5638be69ab3561854f34b",
              "versionType": "git"
            },
            {
              "lessThan": "379d85c7f25f3e05a428225e6b8a65613c6e9b9d",
              "status": "affected",
              "version": "eaea34b23c46bf17b4a5638be69ab3561854f34b",
              "versionType": "git"
            },
            {
              "lessThan": "e098d9cc8859614a7f7baebc96e32a5a16b18ed2",
              "status": "affected",
              "version": "eaea34b23c46bf17b4a5638be69ab3561854f34b",
              "versionType": "git"
            },
            {
              "lessThan": "0ada54ea63e48b9c1608e917ccb7dfadbe86db28",
              "status": "affected",
              "version": "eaea34b23c46bf17b4a5638be69ab3561854f34b",
              "versionType": "git"
            },
            {
              "lessThan": "447c9303942c439a117d9b76ce6d6e2116b38ee7",
              "status": "affected",
              "version": "eaea34b23c46bf17b4a5638be69ab3561854f34b",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/tun.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.6"
            },
            {
              "lessThan": "4.6",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.270",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.221",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.188",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.157",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.109",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.50",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.270",
                  "versionStartIncluding": "4.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.221",
                  "versionStartIncluding": "4.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.188",
                  "versionStartIncluding": "4.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.157",
                  "versionStartIncluding": "4.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.109",
                  "versionStartIncluding": "4.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.50",
                  "versionStartIncluding": "4.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.4",
                  "versionStartIncluding": "4.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc1",
                  "versionStartIncluding": "4.6",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: tun: bound receive headroom\n\ntun_get_user() uses tun-\u003ealign both as skb headroom and when choosing how\nmuch packet data to keep linear. OVS can propagate an oversized headroom\nrequest from another port to TUN or TAP.\n\nWhen align is larger than the usable space in a one-page skb head,\nSKB_MAX_HEAD(align) underflows and the result becomes negative when stored\nin good_linear. That value later wraps when assigned to the size_t linear\nvariable, and tun_alloc_skb() can place skb-\u003edata outside the allocated\nhead.\n\nBound the headroom stored by TUN to the one-page skb-head budget and the\nlargest non-sentinel 16-bit skb header offset. Leave one linear byte for\nraw TUN and a complete Ethernet header for TAP, including NET_IP_ALIGN.\n\nAlso pull the raw-TUN protocol byte and the TAP Ethernet header before\naccessing them, so these checks remain safe for nonlinear skbs supplied by\nother allocation paths."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - tun_get_user() runs on write/sendmsg to /dev/net/tun after ndo_set_rx_headroom stores an oversized tun-\u003ealign. That is a local tun/tap injection path, not parsing of frames received from a remote peer.\nAC:L - The attacker fully controls both sides: inflate rx headroom via netkit IFLA_NETKIT_HEADROOM or the OVS/veth/VXLAN and bridge/veth/GRETAP loops, then write a TUN frame. No race or uninfluenced victim state is required.\nPR:L - TUNSETIFF uses ns_capable(net-\u003euser_ns, CAP_NET_ADMIN) and OVS vport commands use GENL_UNS_ADMIN_PERM, so an unprivileged user with a user+net namespace can create the topology and trigger the write.\nUI:N - The attacker opens /dev/net/tun, configures local net devices, and writes the frame; no separate victim action is required.\nS:U - The out-of-bounds access occurs in the same kernel that handles the local TUN write and yields privilege escalation within that kernel, not a VM/IOMMU boundary crossing.\nC:H - SKB_MAX_HEAD underflow wraps the linear length so tun_alloc_skb()/skb_reserve() can place skb-\u003edata outside the allocated head, turning later header reads and packet processing into out-of-bounds kernel reads.\nI:H - After skb-\u003edata is moved outside the allocated head, skb_copy_datagram_from_iter copies attacker-controlled frame bytes relative to that pointer, an out-of-bounds write usable for kernel corruption and control-flow hijacking.\nA:H - The misplaced skb leads to a kernel oops, BUG() in eth_type_trans/__skb_pull on a nonlinear TAP skb, or panic when the out-of-bounds access is hit."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-14T11:59:35.300Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/ad715e713610d2d5473c3a6498c825ccecf26491"
        },
        {
          "url": "https://git.kernel.org/stable/c/708e87937de93f445225c134a2e20519f9b4ce60"
        },
        {
          "url": "https://git.kernel.org/stable/c/18ef24cdb2eba32e38f1d27f2d02b7b4212e8f76"
        },
        {
          "url": "https://git.kernel.org/stable/c/010eee265d6bd8769b6a523d2a0693d9b3f5df43"
        },
        {
          "url": "https://git.kernel.org/stable/c/379d85c7f25f3e05a428225e6b8a65613c6e9b9d"
        },
        {
          "url": "https://git.kernel.org/stable/c/e098d9cc8859614a7f7baebc96e32a5a16b18ed2"
        },
        {
          "url": "https://git.kernel.org/stable/c/0ada54ea63e48b9c1608e917ccb7dfadbe86db28"
        },
        {
          "url": "https://git.kernel.org/stable/c/447c9303942c439a117d9b76ce6d6e2116b38ee7"
        }
      ],
      "title": "net: tun: bound receive headroom",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-81000",
    "datePublished": "2026-09-11T19:42:54.181Z",
    "dateReserved": "2026-08-26T14:34:25.812Z",
    "dateUpdated": "2026-09-14T11:59:35.300Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

BDU:2026-14928 (CVE-2026-81000)

CVE-2026-81000 (GCVE-0-2026-81000)

Tags

Sightings

Nomenclature

Related by attack behaviour