CVE-2026-64357: Linux kernel · xfs: fix exchmaps reservation limit check
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium · fixed in 7.0.0-1012.12~24.04.1 : update Linux kernel when convenient.
Data as of 26 Oct 2026, 14:05 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 7.0.0-1012.12~24.04.1, 7.0.0-1011.11~24.04.1, 7.0.0-31.31~24.04.1 +7
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 25 Jul 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 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther 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 and should be applied by updating to the fixed Linux kernel versions as provided by the vendor. After applying the update, a system reboot is required. Due to an ABI change, third-party kernel modules must be recompiled and reinstalled. Follow the vendor's update instructions carefully to ensure full remediation.
Description
In the Linux kernel, the following vulnerability has been resolved: xfs: fix exchmaps reservation limit check xfs_exchmaps_estimate_overhead() adds the bmbt and rmapbt overhead to a local resblks variable, but the final UINT_MAX check still tests req->resblks. That is the reservation value from before the overhead was added. The computed value is stored back in req->resblks and later passed to xfs_trans_alloc(), whose block reservation argument is unsigned int. Check the computed reservation so the existing limit applies to the value that will be used.
References
- nvd.nist.gov/vuln/detail/CVE-2026-64357 (opens in a new tab)
- git.kernel.org/stable/c/0a5213bbff62b51c7d4999ac8c7e11ea57d00d45 (opens in a new tab)
- git.kernel.org/stable/c/4707344b0d36d1012c8a1716e20167cd3afdd5f1 (opens in a new tab)
- git.kernel.org/stable/c/a62ef2d13d6e7270dd5e88c6082bf2d0edcd5112 (opens in a new tab)
- git.kernel.org/stable/c/c597c8580d50127fc1221b5a5b653a94d49e23e3 (opens in a new tab)
- ubuntu.com/security/CVE-2026-64357 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-64357 (opens in a new tab)
- git.kernel.org/linus/0a5213bbff62b51c7d4999ac8c7e11ea57d00d45 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8727-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-1 (opens in a new tab)