CVE-2026-99063: Linux kernel · dm ioctl: don't let data_start run past the buffer
Affects Linux kernelSource CVE Database V5
Not known to be exploited · fixed in e5c3f3d8935ecc64c962fb66e6a86dbf79218f61 : update Linux kernel when convenient.
Data as of 26 Oct 2026, 14:18 UTC
Rated Low by Threat Radar's AI analysis · CVSS not yet scored by NVD
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in e5c3f3d8935ecc64c962fb66e6a86dbf79218f61, 98195e822343a656b92e235847ab3e72b1a3f920, 5680b6fb3054677d4ee65d3baba24b649f1b430e +2
Exploitation evidence
Disclosed: evidence found.
CVE published 23 Oct 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 |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in– |
AI-suggested
The vulnerability has been fixed in the Linux kernel in commits identified by hashes e5c3f3d8935ecc64c962fb66e6a86dbf79218f61, 98195e822343a656b92e235847ab3e72b1a3f920, 5680b6fb3054677d4ee65d3baba24b649f1b430e, 725b49c689bbb29ef740b0d6b5ea9390baa9a695, and 9b3fcf519d370df94a56f3b272d9eddffffa5be8. Users should update to a Linux kernel version including these fixes. No additional mitigation is required as the flaw is not exploitable by unprivileged users.
Description
A vulnerability in the Linux kernel's device mapper ioctl interface allows an out-of-bounds read due to improper handling of buffer size calculations. Specifically, the data_start pointer can run past the allocated buffer by seven bytes when userspace requests the minimum buffer size. This flaw can cause a kernel slab-out-of-bounds read, but it requires root privileges to trigger and is not considered a security bug. The issue has been fixed in specific Linux kernel commits.
References
- git.kernel.org/stable/c/98195e822343a656b92e235847ab3e72b1a3f920 (opens in a new tab)
- git.kernel.org/stable/c/e5c3f3d8935ecc64c962fb66e6a86dbf79218f61 (opens in a new tab)
- git.kernel.org/stable/c/5680b6fb3054677d4ee65d3baba24b649f1b430e (opens in a new tab)
- git.kernel.org/stable/c/725b49c689bbb29ef740b0d6b5ea9390baa9a695 (opens in a new tab)
- git.kernel.org/stable/c/9b3fcf519d370df94a56f3b272d9eddffffa5be8 (opens in a new tab)