CVE-2026-80536: Linux kernel · xfs: bounds-check buffer log item's dirty bitmap
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 8.4 High : upgrade to 6.8.0-1036.39 soon.
Data as of 28 Oct 2026, 01:00 UTC
- Patch
- Available – fixed in 6.8.0-1036.39
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 26 Aug 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 the Ubuntu linux-nvidia-tegra package to 6.8.0-1036.39.
Patches and advisories
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.
Description
In the Linux kernel, the following vulnerability has been resolved: xfs: bounds-check buffer log item's dirty bitmap xlog_recover_do_reg_buffer() replays each dirty region described by a buffer log item's bitmap into the buffer read for that item: memcpy(xfs_buf_offset(bp, (uint)bit << XFS_BLF_SHIFT), item->ri_buf[i].iov_base, nbits << XFS_BLF_SHIFT); The destination offset (bit/nbits, from the logged dirty bitmap) and the buffer size (from the logged blf_len) are both attacker-controlled and otherwise unrelated, yet the only thing bounding the copy is an ASSERT(), which compiles away on production kernels. A crafted image logging a small blf_len together with a bitmap bit past the end of that buffer drives the memcpy() past the buffer's allocation, corrupting adjacent kernel heap during mount-time log recovery. This is reachable by anyone who can get a crafted image mounted -- the malicious-filesystem threat model XFS already guards against elsewhere. Turn the ASSERT() into a real XFS_IS_CORRUPT() check that aborts recovery of the buffer with -EFSCORRUPTED, consistent with the validate-and-fail idiom already used in xlog_recover_do_inode_buffer() and xfs_dquot_item_recover.c. xlog_recover_do_reg_buffer() therefore becomes STATIC int and its three callers propagate the error. Found and confirmed with KASAN on a CONFIG_XFS_DEBUG=n build: the crafted image trips a slab-out-of-bounds write before this change and fails recovery cleanly with -EFSCORRUPTED after it.
References
- ubuntu.com/security/CVE-2026-80536 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-80536 (opens in a new tab)
- git.kernel.org/stable/c/f3859c35a4fbc1c1c58431f684f808e43696891d (opens in a new tab)
- git.kernel.org/stable/c/b7528b42813f02724a78fce1da24d69d1bfc4d38 (opens in a new tab)
- git.kernel.org/stable/c/edaf5b6bd625356893da20d69a259b34a9de2694 (opens in a new tab)
- git.kernel.org/stable/c/7e32d4eebae6ca24f8a673c107fd7eca1f47afc2 (opens in a new tab)
- git.kernel.org/stable/c/f7b5fa83e2c192be922121b764415fa8c7549ea1 (opens in a new tab)
- git.kernel.org/stable/c/813f8136a2ce1fee266d02a7df73db6e8a541604 (opens in a new tab)
- git.kernel.org/stable/c/acb4e26295e7f0e685815a3fd3d70bd8329cefa1 (opens in a new tab)
- git.kernel.org/stable/c/f8288214459ead7e87d26e5822f62c14a4f2ed6b (opens in a new tab)
- ubuntu.com/security/notices/USN-8886-1 (opens in a new tab)