CVE-2026-99056: Linux kernel · strparser: make sure __strp_recv isn't running before tearing down the parser
Affects Linux kernelSource CVE Database V5
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
- 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:HExploitation evidence
Disclosed: evidence found.
CVE published 23 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| 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
- git.kernel.org/stable/c/a18dd388045dc7263d99a07db9de4e0f149ca8f1 (opens in a new tab)
- git.kernel.org/stable/c/9f3e9fe1b155e9b4572054d8d140586bc3512ecf (opens in a new tab)
- git.kernel.org/stable/c/d2b5f637b9b67a79a50d42614d10653c13b4e449 (opens in a new tab)
- git.kernel.org/stable/c/eaa3a29004c063d7e9d5ea55636f693f67e6db0f (opens in a new tab)
- git.kernel.org/stable/c/0984ebc631792acf8fff105112ee74a6b8f1efcc (opens in a new tab)