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VulnerabilityPublished Updated

CVE-2026-99056: Linux kernel · strparser: make sure __strp_recv isn't running before tearing down the parser

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.8 High · fixed in eaa3a29004c063d7e9d5ea55636f693f67e6db0f : patch Linux kernel soon.

Data as of 26 Oct 2026, 13:07 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 5% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in eaa3a29004c063d7e9d5ea55636f693f67e6db0f, d2b5f637b9b67a79a50d42614d10653c13b4e449, a18dd388045dc7263d99a07db9de4e0f149ca8f1 +2
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 23 Oct 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ e27cca96cd68fa2c6814c90f9a1cfd36bb68c593, < eaa3a29004c063d7e9d5ea55636f693f67e6db0f
Fixed in
  • eaa3a29004c063d7e9d5ea55636f693f67e6db0f
LinuxLinuxAffected
  • ≥ e27cca96cd68fa2c6814c90f9a1cfd36bb68c593, < d2b5f637b9b67a79a50d42614d10653c13b4e449
Fixed in
  • d2b5f637b9b67a79a50d42614d10653c13b4e449
LinuxLinuxAffected
  • ≥ e27cca96cd68fa2c6814c90f9a1cfd36bb68c593, < a18dd388045dc7263d99a07db9de4e0f149ca8f1
Fixed in
  • a18dd388045dc7263d99a07db9de4e0f149ca8f1
LinuxLinuxAffected
  • ≥ e27cca96cd68fa2c6814c90f9a1cfd36bb68c593, < 0984ebc631792acf8fff105112ee74a6b8f1efcc
Fixed in
  • 0984ebc631792acf8fff105112ee74a6b8f1efcc
LinuxLinuxAffected
  • ≥ e27cca96cd68fa2c6814c90f9a1cfd36bb68c593, < 9f3e9fe1b155e9b4572054d8d140586bc3512ecf
Fixed in
  • 9f3e9fe1b155e9b4572054d8d140586bc3512ecf
LinuxLinuxAffected
  • =5.6
Fixed in–

AI-suggested

A fix is available and has been applied in multiple commits to the Linux kernel. Users and administrators should upgrade to a fixed kernel version that includes these patches. Since this is not a cloud service, manual patching is required. No additional mitigations are indicated by the vendor advisory.

Description

CVE-2026-99056 is a high-severity vulnerability in the Linux kernel's strparser component, specifically affecting version 5.6. It involves a race condition where the __strp_recv function may still be running when the parser is torn down, potentially leading to use-after-free (UAF) conditions. The issue primarily affects the espintcp user of strp_recv. A patch has been applied to add locking mechanisms to ensure that any in-flight __strp_recv calls complete before teardown, preventing crashes and exploitation. A reproducer and exploit have been published, highlighting the practical risk of this flaw.

References

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