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VulnerabilityPublished Updated

CVE-2026-98405: Linux kernel · smb: client: fix missing iov bounds check in parse_posix_sids()

Affects Linux kernelSource CVE Database V5

0

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

CVSS 3.1 base score
8.1High
How severe the flaw is on the 0–10 CVSS scale.
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:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 14 Oct 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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

ProductAffectedFixed in
LinuxLinuxAffected
  • >=6.6.32 <6.6.158
Fixed in
  • eac6917a42899aad0617bbf04798c5dd946a1fe5
  • d91b9a3b2b38e5ac1b51e9e5b23fe53ad7b49644
  • b862996e5105be1293da9cdc85da77b76021c3bd
  • b09d092eb24ad0110f16a9b7c1ed5d2a0c1733dc
  • 6.6.158
  • 2f8ed71aaaba3bc8b19cd9930cc62e63e142b299
LinuxLinuxAffected
  • =6.8
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

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