Vulnerability-Lookup

FKIE_CVE-2026-31772

Vulnerability from fkie_nvd - Published: 2026-05-01 15:16 - Updated: 2026-05-11 20:42

Severity ?

7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Summary

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_sync: fix stack buffer overflow in hci_le_big_create_sync hci_le_big_create_sync() uses DEFINE_FLEX to allocate a struct hci_cp_le_big_create_sync on the stack with room for 0x11 (17) BIS entries. However, conn->num_bis can hold up to HCI_MAX_ISO_BIS (31) entries — validated against ISO_MAX_NUM_BIS (0x1f) in the caller hci_conn_big_create_sync(). When conn->num_bis is between 18 and 31, the memcpy that copies conn->bis into cp->bis writes up to 14 bytes past the stack buffer, corrupting adjacent stack memory. This is trivially reproducible: binding an ISO socket with bc_num_bis = ISO_MAX_NUM_BIS (31) and calling listen() will eventually trigger hci_le_big_create_sync() from the HCI command sync worker, causing a KASAN-detectable stack-out-of-bounds write: BUG: KASAN: stack-out-of-bounds in hci_le_big_create_sync+0x256/0x3b0 Write of size 31 at addr ffffc90000487b48 by task kworker/u9:0/71 Fix this by changing the DEFINE_FLEX count from the incorrect 0x11 to HCI_MAX_ISO_BIS, which matches the maximum number of BIS entries that conn->bis can actually carry.

References

URL	Tags
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/aba0aea354015794e8312dd7efe726967e58aefe	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/bc39a094730ce062fa034a529c93147c096cb488	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/eaf32002ca7b1ba51c9f140991fd9febe6de79f0	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/f5d446624345d309e7a4a1b27ea9f028d6a8c5d9	Patch

Impacted products

Vendor	Product	Version
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	6.13
linux	linux_kernel	7.0
linux	linux_kernel	7.0
linux	linux_kernel	7.0
linux	linux_kernel	7.0
linux	linux_kernel	7.0
linux	linux_kernel	7.0

JSON

To clipboard

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      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_sync: fix stack buffer overflow in hci_le_big_create_sync\n\nhci_le_big_create_sync() uses DEFINE_FLEX to allocate a\nstruct hci_cp_le_big_create_sync on the stack with room for 0x11 (17)\nBIS entries.  However, conn-\u003enum_bis can hold up to HCI_MAX_ISO_BIS (31)\nentries \u2014 validated against ISO_MAX_NUM_BIS (0x1f) in the caller\nhci_conn_big_create_sync().  When conn-\u003enum_bis is between 18 and 31,\nthe memcpy that copies conn-\u003ebis into cp-\u003ebis writes up to 14 bytes\npast the stack buffer, corrupting adjacent stack memory.\n\nThis is trivially reproducible: binding an ISO socket with\nbc_num_bis = ISO_MAX_NUM_BIS (31) and calling listen() will\neventually trigger hci_le_big_create_sync() from the HCI command\nsync worker, causing a KASAN-detectable stack-out-of-bounds write:\n\n  BUG: KASAN: stack-out-of-bounds in hci_le_big_create_sync+0x256/0x3b0\n  Write of size 31 at addr ffffc90000487b48 by task kworker/u9:0/71\n\nFix this by changing the DEFINE_FLEX count from the incorrect 0x11 to\nHCI_MAX_ISO_BIS, which matches the maximum number of BIS entries that\nconn-\u003ebis can actually carry."
    }
  ],
  "id": "CVE-2026-31772",
  "lastModified": "2026-05-11T20:42:32.927",
  "metrics": {
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          "attackVector": "LOCAL",
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          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
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      "source": "nvd@nist.gov",
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}

CVE-2026-31772 (GCVE-0-2026-31772)

Vulnerability from cvelistv5 – Published: 2026-05-01 14:15 – Updated: 2026-05-11 22:15

Title

Bluetooth: hci_sync: fix stack buffer overflow in hci_le_big_create_sync

Summary

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

References

4 references

URL	Tags
https://git.kernel.org/stable/c/f5d446624345d309e…
https://git.kernel.org/stable/c/aba0aea354015794e…
https://git.kernel.org/stable/c/eaf32002ca7b1ba51…
https://git.kernel.org/stable/c/bc39a094730ce062f…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 91d19383b7ed035e22165ae5c836e50bb9f95fbe , < f5d446624345d309e7a4a1b27ea9f028d6a8c5d9 (git) Affected: 42ecf1947135110ea08abeaca39741636f9a2285 , < aba0aea354015794e8312dd7efe726967e58aefe (git) Affected: 42ecf1947135110ea08abeaca39741636f9a2285 , < eaf32002ca7b1ba51c9f140991fd9febe6de79f0 (git) Affected: 42ecf1947135110ea08abeaca39741636f9a2285 , < bc39a094730ce062fa034a529c93147c096cb488 (git) Affected: 8958e1cee4e2eac1a5b825caa4dd96ce9ed975dd (git)
Linux	Linux	Affected: 6.13 Unaffected: 0 , < 6.13 (semver) Unaffected: 6.12.81 , ≤ 6.12.* (semver) Unaffected: 6.18.22 , ≤ 6.18.* (semver) Unaffected: 6.19.12 , ≤ 6.19.* (semver) Unaffected: 7.0 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

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      "title": "Bluetooth: hci_sync: fix stack buffer overflow in hci_le_big_create_sync",
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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.

Detection rules are retrieved from Rulezet.

Action not permitted

FKIE_CVE-2026-31772

CVE-2026-31772 (GCVE-0-2026-31772)

Tags

Sightings

Nomenclature