Vulnerability-Lookup

GHSA-CXJ6-CG32-R3FC

Vulnerability from github – Published: 2026-10-23 15:31 – Updated: 2026-10-24 15:32

Details

In the Linux kernel, the following vulnerability has been resolved:

strparser: make sure __strp_recv isn't running before tearing down the parser

The comment above strp_done() claims that if strp is stopped, strp_recv will no longer be called. That's only true if the caller has a mechanism (eg locking) to guarantee that strp_recv() calls that started before strp_stop() have completed by the time we call strp_done().

This adds a dummy lock_sock/release_sock pair to guarantee that any in-flight strp_recv() (which runs under either bh_lock_sock or lock_sock, depending if it's called from ->sk_data_ready or strp_work) has completed.

Only espintcp can be affected by this race condition, but this patch makes sure no future user of strp can have the bug.

This could crash on strp->sk ("general mode" of strp), but this mode has been here for 9 years and has never been used. It'll be gone soon, no point worrying about it.

Switch the stopped/paused/etc bits to u8's to avoid races between strp_stop() and strp_pause/unpause().

A reproducer has been published and turns the possible UAF into an exploit [1].

Severity

7.8 (High)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-99056"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-23T13:17:29Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nstrparser: make sure __strp_recv isn\u0027t running before tearing down the parser\n\nThe comment above strp_done() claims that if strp is stopped,\nstrp_recv will no longer be called. That\u0027s only true if the caller has\na mechanism (eg locking) to guarantee that strp_recv() calls that\nstarted before strp_stop() have completed by the time we call\nstrp_done().\n\nThis adds a dummy lock_sock/release_sock pair to guarantee that any\nin-flight strp_recv() (which runs under either bh_lock_sock or\nlock_sock, depending if it\u0027s called from -\u003esk_data_ready or strp_work)\nhas completed.\n\nOnly espintcp can be affected by this race condition, but this patch\nmakes sure no future user of strp can have the bug.\n\nThis could crash on strp-\u003esk (\"general mode\" of strp), but this mode\nhas been here for 9 years and has never been used. It\u0027ll be gone soon,\nno point worrying about it.\n\nSwitch the stopped/paused/etc bits to u8\u0027s to avoid races between\nstrp_stop() and strp_pause/unpause().\n\nA reproducer has been published and turns the possible UAF into an\nexploit [1].",
  "id": "GHSA-cxj6-cg32-r3fc",
  "modified": "2026-10-24T15:32:51Z",
  "published": "2026-10-23T15:31:36Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-99056"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0984ebc631792acf8fff105112ee74a6b8f1efcc"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9f3e9fe1b155e9b4572054d8d140586bc3512ecf"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a18dd388045dc7263d99a07db9de4e0f149ca8f1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d2b5f637b9b67a79a50d42614d10653c13b4e449"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/eaa3a29004c063d7e9d5ea55636f693f67e6db0f"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-99056 (GCVE-0-2026-99056)

Vulnerability from cvelistv5 – Published: 2026-10-23 12:22 – Updated: 2026-10-24 14:10

Title

strparser: make sure __strp_recv isn't running before tearing down the parser

Summary

In the Linux kernel, the following vulnerability has been resolved: strparser: make sure __strp_recv isn't running before tearing down the parser The comment above strp_done() claims that if strp is stopped, strp_recv will no longer be called. That's only true if the caller has a mechanism (eg locking) to guarantee that strp_recv() calls that started before strp_stop() have completed by the time we call strp_done(). This adds a dummy lock_sock/release_sock pair to guarantee that any in-flight strp_recv() (which runs under either bh_lock_sock or lock_sock, depending if it's called from ->sk_data_ready or strp_work) has completed. Only espintcp can be affected by this race condition, but this patch makes sure no future user of strp can have the bug. This could crash on strp->sk ("general mode" of strp), but this mode has been here for 9 years and has never been used. It'll be gone soon, no point worrying about it. Switch the stopped/paused/etc bits to u8's to avoid races between strp_stop() and strp_pause/unpause(). A reproducer has been published and turns the possible UAF into an exploit [1].

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 CNA under the mitre root

CNA scorecard D 53/100 over 7067 records in the last 180 days details

References

5 references

URL	Tags
https://git.kernel.org/stable/c/a18dd388045dc7263…
https://git.kernel.org/stable/c/9f3e9fe1b155e9b45…
https://git.kernel.org/stable/c/d2b5f637b9b67a79a…
https://git.kernel.org/stable/c/eaa3a29004c063d7e…
https://git.kernel.org/stable/c/0984ebc631792acf8…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 , < a18dd388045dc7263d99a07db9de4e0f149ca8f1 (git) Affected: e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 , < 9f3e9fe1b155e9b4572054d8d140586bc3512ecf (git) Affected: e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 , < d2b5f637b9b67a79a50d42614d10653c13b4e449 (git) Affected: e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 , < eaa3a29004c063d7e9d5ea55636f693f67e6db0f (git) Affected: e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 , < 0984ebc631792acf8fff105112ee74a6b8f1efcc (git)
Linux	Linux	Affected: 5.6 Unaffected: 0 , < 5.6 (semver) Unaffected: 6.6.160 , ≤ 6.6.* (semver) Unaffected: 6.12.113 , ≤ 6.12.* (semver) Unaffected: 6.18.57 , ≤ 6.18.* (semver) Unaffected: 7.2.11 , ≤ 7.2.* (semver) Unaffected: 7.3 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "Documentation/networking/strparser.rst",
            "include/net/strparser.h",
            "net/strparser/strparser.c"
          ],
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              "versionType": "git"
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              "versionType": "git"
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            "include/net/strparser.h",
            "net/strparser/strparser.c"
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          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.6"
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              "status": "unaffected",
              "version": "6.12.113",
              "versionType": "semver"
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              "status": "unaffected",
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            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.11",
              "versionType": "semver"
            },
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              "status": "unaffected",
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              "versionType": "original_commit_for_fix"
            }
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      "cpeApplicability": [
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          "nodes": [
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              "cpeMatch": [
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          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nstrparser: make sure __strp_recv isn\u0027t running before tearing down the parser\n\nThe comment above strp_done() claims that if strp is stopped,\nstrp_recv will no longer be called. That\u0027s only true if the caller has\na mechanism (eg locking) to guarantee that strp_recv() calls that\nstarted before strp_stop() have completed by the time we call\nstrp_done().\n\nThis adds a dummy lock_sock/release_sock pair to guarantee that any\nin-flight strp_recv() (which runs under either bh_lock_sock or\nlock_sock, depending if it\u0027s called from -\u003esk_data_ready or strp_work)\nhas completed.\n\nOnly espintcp can be affected by this race condition, but this patch\nmakes sure no future user of strp can have the bug.\n\nThis could crash on strp-\u003esk (\"general mode\" of strp), but this mode\nhas been here for 9 years and has never been used. It\u0027ll be gone soon,\nno point worrying about it.\n\nSwitch the stopped/paused/etc bits to u8\u0027s to avoid races between\nstrp_stop() and strp_pause/unpause().\n\nA reproducer has been published and turns the possible UAF into an\nexploit [1]."
        }
      ],
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              "value": "AV:L - An unprivileged local process can attach \"espintcp\" with setsockopt(TCP_ULP), then use a loopback peer to drive espintcp_data_ready()-\u003estrp_data_ready()-\u003e__strp_recv() while close() reaches espintcp_close()-\u003estrp_done(); a network peer alone cannot initiate the required local teardown.\nAC:L - The same process controls both race sides: it sets a finite SO_RCVTIMEO, sends complete keepalives plus a partial header that makes espintcp_parse() return 0 and strp_start_timer() rearm after strp_done() cancels, and concurrently closes the target socket. The race is repeatable and publicly exploited.\nPR:L - __sys_setsockopt()-\u003etcp_setsockopt()-\u003etcp_set_ulp()-\u003eespintcp_init_sk() contains no capability or authentication check for an already registered \"espintcp\" ULP. An ordinary local user can create the TCP pair, set the timeout, attach the ULP, and close it.\nUI:N - The attacking process performs the socket creation, TCP_ULP attachment, traffic generation, close, and heap reclaim itself; no action by another user is required.\nS:U - The reclaimed espintcp_ctx and its msg_timer_work execute within the host kernel reached by the attacking local process; this is a conventional local kernel privilege escalation and crosses no VM, IOMMU, or separate security authority.\nC:H - The freed espintcp_ctx can be reclaimed with a controlled user_key_payload, including msg_timer_work.timer.function and callback operands. The resulting kernel callback control and root execution permit access to arbitrary protected memory.\nI:H - The controlled timer.function and RDI-relative operands let the demonstrated iocg_flush_stat_upward gadget perform a chosen delta write to modprobe_path, producing root code execution.\nA:H - If the freed msg_timer_work is not coherently reclaimed, timer expiry consumes stale work_struct fields or calls an invalid timer.function, causing a kernel fault or panic; the published exploit also documents a crash-only variant."
            }
          ]
        }
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        "dateUpdated": "2026-10-24T14:10:15.756Z",
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        {
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      "title": "strparser: make sure __strp_recv isn\u0027t running before tearing down the parser",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-99056",
    "datePublished": "2026-10-23T12:22:42.234Z",
    "dateReserved": "2026-09-25T10:25:14.388Z",
    "dateUpdated": "2026-10-24T14:10:15.756Z",
    "state": "PUBLISHED"
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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.

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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.
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