CVE-2026-97991: Linux kernel · vdpa_sim_blk: reject out-of-range sector starts
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 1% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 25 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 is available that rejects out-of-range sector start requests at or beyond the capacity boundary, preventing the unsigned capacity subtraction underflow and subsequent out-of-bounds memory access. Users should apply the official kernel updates for the affected linux-hwe-edge versions to remediate this vulnerability.
Description
A vulnerability in the Linux kernel's vdpa_sim_blk component allows out-of-range sector start requests to bypass validation, leading to out-of-bounds memory access. This occurs because the function vdpasim_blk_check_range() logs invalid start sectors but continues processing, causing an unsigned capacity subtraction underflow. This flaw affects three request paths that perform out-of-bounds reads or writes, potentially impacting data integrity and system stability.
References
- ubuntu.com/security/CVE-2026-97991 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-97991 (opens in a new tab)
- git.kernel.org/stable/c/d6dac17e20fd2abd0eb8c09d69fccf7426e12bcf (opens in a new tab)
- git.kernel.org/stable/c/14acb0d44b7d90a077beb7b92b444b90bafda9d9 (opens in a new tab)
- git.kernel.org/stable/c/a8a1413a2cfdbedc896249f461d6d92efbbfe21f (opens in a new tab)
- git.kernel.org/stable/c/0a8693f00c408d85f086ad85d29e7030bf1e2055 (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-97991 (opens in a new tab)
- git.kernel.org/stable/c/000c6300776ceaf6b715780113f4275b1be4195b (opens in a new tab)
- git.kernel.org/stable/c/2ff2a8d063fdfa1e1479fb1fe2e3356a2ce89018 (opens in a new tab)
- git.kernel.org/stable/c/36ef4d8527f71648f00347f6ba759f0b7e5e0977 (opens in a new tab)