CVE-2026-98405: Linux kernel · smb: client: fix missing iov bounds check in parse_posix_sids()
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 8.1 High · fixed in eac6917a42899aad0617bbf04798c5dd946a1fe5 : patch Linux kernel soon.
Data as of 26 Oct 2026, 13:47 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 40% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in eac6917a42899aad0617bbf04798c5dd946a1fe5, d91b9a3b2b38e5ac1b51e9e5b23fe53ad7b49644, b862996e5105be1293da9cdc85da77b76021c3bd +3
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 14 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
|
| LinuxLinux | Affected
| Fixed in– |
AI-suggested
A fix is available in Linux kernel version 6.6.158 and later. Users and administrators should upgrade affected Linux kernel versions (>=6.6.32 <6.6.158 and =6.8) to 6.6.158 or apply the corresponding patches identified by commit hashes provided in the established facts. No additional mitigation steps are indicated by the vendor advisory.
Description
CVE-2026-98405 is a high-severity vulnerability in the Linux kernel's SMB client implementation. It involves a missing bounds check in the parse_posix_sids() function, where the server-supplied out_len is not validated against the actual length of the received iov buffer. This flaw allows out-of-bounds reads into adjacent kernel memory if a malicious server provides an inflated out_len. The issue has been fixed by rejecting responses with invalid sidsbuf_end calculations that exceed buffer boundaries or cause pointer wraparound.
References
- git.kernel.org/stable/c/d91b9a3b2b38e5ac1b51e9e5b23fe53ad7b49644 (opens in a new tab)
- git.kernel.org/stable/c/b862996e5105be1293da9cdc85da77b76021c3bd (opens in a new tab)
- git.kernel.org/stable/c/2f8ed71aaaba3bc8b19cd9930cc62e63e142b299 (opens in a new tab)
- git.kernel.org/stable/c/eac6917a42899aad0617bbf04798c5dd946a1fe5 (opens in a new tab)
- git.kernel.org/stable/c/b09d092eb24ad0110f16a9b7c1ed5d2a0c1733dc (opens in a new tab)