CVE-2026-23234: Linux kernel · f2fs: fix to avoid UAF in f2fs_write_end_io()
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High · fixed in 5.15.0-1112.119~20.04.1 : patch Linux kernel soon.
Data as of 26 Oct 2026, 16:03 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 5.15.0-1112.119~20.04.1, 5.15.0-1117.126~20.04.1, 5.15.0-1117.126~20.04.2 +63
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 4 Mar 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?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-oraclepkg:deb/ubuntu/linux-oracle?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 to affected Linux kernel versions. The vendor advisory from Ubuntu confirms that this issue is fixed in updated kernel releases. Users should update their systems to the patched kernel versions as provided by their distribution vendors.
Description
A use-after-free vulnerability in the Linux kernel's f2fs_write_end_io() function was identified and resolved. The flaw was caused by a race condition involving the freeing of the superblock info structure (sbi) while it was still being accessed during writeback completion. The issue was fixed by relocating the checkpoint thread wakeup flow to ensure safe access to the sbi structure. This vulnerability affects specific Linux kernel versions and has a CVSS score of 7.8. An official patch is available to address this issue.
References
- ubuntu.com/security/CVE-2026-23234 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-23234 (opens in a new tab)
- git.kernel.org/linus/ce2739e482bce8d2c014d76c4531c877f382aa54 (opens in a new tab)
- git.kernel.org/stable/c/0fb58aff0dafd6837cc91f4154f3ed6e020358fa (opens in a new tab)
- git.kernel.org/stable/c/2f67ff1e15a8a4d0e4ffc6564ab20d03d7398fe9 (opens in a new tab)
- git.kernel.org/stable/c/505e1c0530db6152cab3feef8e3e4da3d3e358c9 (opens in a new tab)
- git.kernel.org/stable/c/995030be4ce6338c6ff814583c14166446a64008 (opens in a new tab)
- git.kernel.org/stable/c/a42f99be8a16b32a0bb91bb6dda212a6ad61be5d (opens in a new tab)
- git.kernel.org/stable/c/acc2c97fc0005846e5cf11b5ba3189fef130c9b3 (opens in a new tab)
- git.kernel.org/stable/c/ce2739e482bce8d2c014d76c4531c877f382aa54 (opens in a new tab)
- git.kernel.org/stable/c/cf4a9e1bc8129eb63fda5f8bdcd8d87f0bd76f42 (opens in a new tab)
- ubuntu.com/security/notices/USN-8492-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8492-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8497-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8498-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8499-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8492-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8492-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8492-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-8575-1 (opens in a new tab)