CVE-2026-23121: Linux kernel · mISDN: annotate data-race around dev->work
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium · fixed in 5.15.0-1105.112~20.04.1 : update Linux kernel when convenient.
Data as of 26 Oct 2026, 12:55 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 1% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 5.15.0-1105.112~20.04.1, 5.15.0-1110.119~20.04.1, 5.15.0-1106.115~20.04.1 +59
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 14 Feb 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 |
|---|---|---|
Ubuntu 25.10linuxpkg:deb/ubuntu/linux@6.17.0-40.40?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-awspkg:deb/ubuntu/linux-aws@6.17.0-1019.19?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-azurepkg:deb/ubuntu/linux-azure@6.17.0-1020.20?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde@6.17.0-1017.17?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-gcppkg:deb/ubuntu/linux-gcp@6.17.0-1020.22?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-oraclepkg:deb/ubuntu/linux-oracle@6.17.0-1018.18?arch=source&distro=questingOther 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
An official patch is available and should be applied. The Ubuntu advisory USN-8162-1 confirms that this and other Linux kernel vulnerabilities have been fixed in updated kernel packages. Users should update to the fixed kernel versions and reboot their systems. Due to ABI changes, recompilation and reinstallation of third-party kernel modules may be required. No additional mitigation steps are indicated.
Description
A data race vulnerability was identified and resolved in the Linux kernel's Modular ISDN (mISDN) driver. The issue involved unsynchronized access to the dev->work field in mISDN_read() and mISDN_poll(), leading to potential kernel instability. The vulnerability was detected by Kernel Concurrency Sanitizer (KCSAN) and fixed by adding READ_ONCE()/WRITE_ONCE() annotations to prevent race conditions. This flaw affects specific Linux kernel versions and has a medium severity rating with an impact on availability.
References
- ubuntu.com/security/CVE-2026-23121 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-23121 (opens in a new tab)
- git.kernel.org/linus/8175dbf174d487afab81e936a862a8d9b8a1ccb6 (opens in a new tab)
- git.kernel.org/stable/c/13f3b3b87068898056db4c79ee67052fbde11d43 (opens in a new tab)
- git.kernel.org/stable/c/7ac345a93af31358e18e9606eb7b354691bf6757 (opens in a new tab)
- git.kernel.org/stable/c/8175dbf174d487afab81e936a862a8d9b8a1ccb6 (opens in a new tab)
- git.kernel.org/stable/c/aa6e33cd74ca4965f2bbcb025e0b672fb0168a69 (opens in a new tab)
- git.kernel.org/stable/c/accc3f8266d2a49881dbcf78c459477f4efa0ff3 (opens in a new tab)
- git.kernel.org/stable/c/d5d99cb9e0839093cd53aa3b28176fce2f820ca0 (opens in a new tab)
- git.kernel.org/stable/c/fc8ba17fd3337bd8b1913c30b95df0fee00d8fb7 (opens in a new tab)
- ubuntu.com/security/notices/USN-8162-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8180-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8180-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8186-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8187-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8188-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8180-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8180-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8180-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-8243-1 (opens in a new tab)