CVE-2026-80807: Linux kernel · nilfs2: reject invalid block index in GC ioctl
Affects Linux kernelSource GCVE Database
Not known to be exploited.
Data as of 26 Oct 2026, 14:05 UTC
Rated by Threat Radar · CVSS not yet scored by NVD
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 9% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Exploitation evidence
Disclosed: evidence found.
CVE published 4 Sep 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
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 fix has been implemented that adds range checks on the parameters 'vd_offset' and 'vd_vblocknr' in the nilfs_vdesc structure to prevent invalid page index insertions. Users should update to a Linux kernel version that includes this fix once available.
Description
In the Linux kernel, the following vulnerability has been resolved: nilfs2: reject invalid block index in GC ioctl Syzbot reported list corruption caused by a double list_add_tail() call on bh->b_assoc_buffers within nilfs_lookup_dirty_data_buffers(). Analysis revealed that the root cause was the insertion of a page/folio with a page index of ULONG_MAX into the page cache via the GC ioctl. filemap_get_folios_tag(), called by nilfs_lookup_dirty_data_buffers(), repeatedly detects a dirty folio with a page index of ULONG_MAX due to index wrap-around, leading to duplicate processing of dirty buffers. As a preparatory step, the GC ioctl loads the page/folio of the block to be moved during GC and inserts it into the page cache based on information in the nilfs_vdesc structure passed as an argument. Normally, this does not cause issues because the user-space GC library configures the nilfs_vdesc structure properly. However, since there is no range check on the parameters determining the page index, a request with artificially crafted parameters -- such as those generated by Syzbot -- can result in a page/folio being inserted with a page index of ULONG_MAX, triggering the above problem. This resolves the issue by checking the ranges of 'vd_offset' and 'vd_vblocknr' in the nilfs_vdesc structure that determine the page index, thereby preventing the invalid page/folio insertions.
References
- nvd.nist.gov/vuln/detail/CVE-2026-80807 (opens in a new tab)
- git.kernel.org/stable/c/3bd064ccc70b85f9a3d53aece29dc8473be5a226 (opens in a new tab)
- git.kernel.org/stable/c/68aa9ab6f8f2895713aa6ddf781463ed8ea5ba44 (opens in a new tab)
- git.kernel.org/stable/c/898404cdf882d7b54f1132f75570984ca3214796 (opens in a new tab)
- git.kernel.org/stable/c/a1735eae55448bc79c2da6593455791e886f6ed8 (opens in a new tab)
- git.kernel.org/stable/c/a5e776e2937581d67ec5b9b4d27b0f70d7baa6b1 (opens in a new tab)
- git.kernel.org/stable/c/ba8a8b563a28d358c45c62a306d421434a058648 (opens in a new tab)
- git.kernel.org/stable/c/e447f7edb99bd00cec63d6f3049e2e5074946f71 (opens in a new tab)
- git.kernel.org/stable/c/ec6ddf271dfa4c7e3147bc2c8b2bad4315f316a1 (opens in a new tab)
- git.kernel.org/stable/c/fbcfb75c20d71a5b542ad4ac3b79d10b997c8152 (opens in a new tab)
- ubuntu.com/security/CVE-2026-80807 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-80807 (opens in a new tab)
- git.kernel.org/linus/a1735eae55448bc79c2da6593455791e886f6ed8 (opens in a new tab)