CVE-2026-99056: Linux kernel · strparser: make sure __strp_recv isn't running before tearing down the parser
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High.
Data as of 28 Oct 2026, 01:41 UTC
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
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10linuxpkg:deb/ubuntu/linux?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-oraclepkg:deb/ubuntu/linux-oracle?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix is available that adds locking to ensure __strp_recv is not running during parser teardown, preventing the race condition. Users should apply the official patches for the affected Linux kernel versions listed. Since this is a kernel-level vulnerability, updating to patched kernel releases is the recommended mitigation. No alternative workarounds are indicated.
Description
CVE-2026-99056 is a high-severity vulnerability in the Linux kernel's strparser component. It involves a race condition where the __strp_recv function may still be running when the parser is being torn down, potentially leading to use-after-free (UAF) conditions. This flaw affects certain Linux kernel versions and has been addressed by adding locking mechanisms to ensure no in-flight __strp_recv calls are active during teardown. A reproducer exists that can turn the UAF into an exploit. The vulnerability primarily affects the espintcp user but the patch prevents future users from encountering this bug.
References
- ubuntu.com/security/CVE-2026-99056 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-99056 (opens in a new tab)
- git.kernel.org/stable/c/0984ebc631792acf8fff105112ee74a6b8f1efcc (opens in a new tab)
- git.kernel.org/stable/c/9f3e9fe1b155e9b4572054d8d140586bc3512ecf (opens in a new tab)
- git.kernel.org/stable/c/a18dd388045dc7263d99a07db9de4e0f149ca8f1 (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)