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VulnerabilityPublished Updated

CVE-2026-99042: Linux kernel · io_uring/net: populate CONNECT filter fields for 24-byte sockaddr_in6

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 8.4 High : upgrade to aa5d5f8e502318e783545ba5d04bb40130b83e20 or 596a955d2d01b7e29d9fed60ebcf7c4ba518b8e5 soon.

Data as of 26 Oct 2026, 14:18 UTC

CVSS 3.1 base score
8.4High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 5% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in aa5d5f8e502318e783545ba5d04bb40130b83e20, 596a955d2d01b7e29d9fed60ebcf7c4ba518b8e5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 23 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 Linux kernel to aa5d5f8e502318e783545ba5d04bb40130b83e20 or 596a955d2d01b7e29d9fed60ebcf7c4ba518b8e5.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 899bea8248cee35d54760a5e7d61a76af8e64411, < aa5d5f8e502318e783545ba5d04bb40130b83e20
Fixed in
  • aa5d5f8e502318e783545ba5d04bb40130b83e20
LinuxLinuxAffected
  • ≥ 899bea8248cee35d54760a5e7d61a76af8e64411, < 596a955d2d01b7e29d9fed60ebcf7c4ba518b8e5
Fixed in
  • 596a955d2d01b7e29d9fed60ebcf7c4ba518b8e5
LinuxLinuxAffected
  • =7.2
Fixed in–

AI-suggested

A fix for this vulnerability is available and has been applied in Linux kernel versions after 7.2, as indicated by the fixed commits. Users should upgrade to a fixed kernel version containing the patches identified by commits aa5d5f8e502318e783545ba5d04bb40130b83e20 and 596a955d2d01b7e29d9fed60ebcf7c4ba518b8e5. No additional mitigation is required if running a patched kernel.

Description

CVE-2026-99042 is a vulnerability in the Linux kernel's io_uring networking code where a mismatch in address length checks allows bypassing of IPv6 connect filters. Specifically, the filter fields for connect.port and connect.v6_addr are not populated correctly for 24-byte sockaddr_in6 structures, causing filters that deny certain IPv6 ports or addresses to be bypassed. This issue has been fixed by adjusting the threshold to use SIN6_LEN_RFC2133 (24 bytes) as the correct length check.

References

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