CVE-2026-97555: Linux kernel · smb: client: fix heap overflow in DACL owner/group rewrite
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 8.8 High · fixed in fb736ab4fb8c4fdb8b2f9ccd3a62e03d11549ca1 : patch Linux kernel soon.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.5% chance of exploitation in 30 days – higher than 44% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in fb736ab4fb8c4fdb8b2f9ccd3a62e03d11549ca1, d5cea6766ae1868a51c7d17d77d065b4f55c587f, 7fa84c9ca690643f429ae2709584a47e74b572c9 +2
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/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
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
A fix is available in Linux kernel versions that include the specified commits (fb736ab4fb8c4fdb8b2f9ccd3a62e03d11549ca1 and others). Users should update from version 5.12 to a patched kernel release containing these fixes. No other specific mitigations are indicated.
Description
A heap overflow vulnerability in the Linux kernel's SMB client was fixed. The flaw occurs during rewriting of DACL owner/group SIDs when longer replacement SIDs cause buffer overflow due to insufficient allocation size. This can lead to memory corruption. The issue affects Linux kernel version 5.12 and was resolved by allocating sufficient buffer space for worst-case SID sizes.
References
- git.kernel.org/stable/c/d5cea6766ae1868a51c7d17d77d065b4f55c587f (opens in a new tab)
- git.kernel.org/stable/c/fb736ab4fb8c4fdb8b2f9ccd3a62e03d11549ca1 (opens in a new tab)
- git.kernel.org/stable/c/7fa84c9ca690643f429ae2709584a47e74b572c9 (opens in a new tab)
- git.kernel.org/stable/c/2a9aee9ef5622d58d8aafaa3263b3ffe70e2d9dd (opens in a new tab)
- git.kernel.org/stable/c/0ee150794c75bcd0be0e24ff3394f433cbae18cc (opens in a new tab)