CVE-2025-39800: Linux kernel · btrfs: abort transaction on unexpected eb generation at btrfs_copy_root()
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High · fixed in 6.8.0-1046.49~22.04.1 : patch Linux kernel soon.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 4% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 6.8.0-1046.49~22.04.1, 6.8.0-1051.57~22.04.1, 6.8.0-1047.50~22.04.2 +24
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 15 Sep 2025
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 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde@6.17.0-1017.17?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSlinuxpkg:deb/ubuntu/linux@6.8.0-100.100?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-awspkg:deb/ubuntu/linux-aws@6.8.0-1046.49?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-aws-6.14pkg:deb/ubuntu/linux-aws-6.14@6.14.0-1018.18~24.04.1?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure@6.8.0-1046.52?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azure-6.11pkg:deb/ubuntu/linux-azure-6.11@6.11.0-1018.18~24.04.1?arch=source&distro=nobleOther 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 patch is available that changes the behavior to abort the transaction and return an error when an unexpected extent buffer generation is detected during btrfs_copy_root(). Users should apply the official Linux kernel updates that include this fix. The vendor advisory confirms the availability of the fix. No additional mitigation steps are indicated.
Description
A vulnerability in the Linux kernel's btrfs filesystem was resolved where the system would only warn on unexpected extent buffer generations during btrfs_copy_root(), allowing metadata with unexpected generations to persist. The fix changes this behavior to abort the transaction and return an error instead. This vulnerability affects specific Linux kernel versions and has a CVSS score of 7.8, indicating a high impact on confidentiality, integrity, and availability.
References
- ubuntu.com/security/CVE-2025-39800 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-39800 (opens in a new tab)
- git.kernel.org/linus/33e8f24b52d2796b8cfb28c19a1a7dd6476323a8 (opens in a new tab)
- git.kernel.org/stable/c/33e8f24b52d2796b8cfb28c19a1a7dd6476323a8 (opens in a new tab)
- git.kernel.org/stable/c/4290e34fb87ae556b12c216efd0ae91583446b7a (opens in a new tab)
- git.kernel.org/stable/c/4734255ef39b416864139dcda96a387fe5f33a6a (opens in a new tab)
- git.kernel.org/stable/c/da2124719f386b6e5d4d4b1a2e67c440e4d5892f (opens in a new tab)
- git.kernel.org/stable/c/f4f5bd9251a4cbe55aaa05725c6c3c32ad1f74b3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8028-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8028-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8031-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8028-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8028-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8028-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-8031-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8028-6 (opens in a new tab)
- ubuntu.com/security/notices/USN-8031-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8052-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8028-7 (opens in a new tab)
- ubuntu.com/security/notices/USN-8028-8 (opens in a new tab)