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VulnerabilityPublished Updated

CVE-2026-80554: Linux kernel · s390/vfio_ccw: Limit the number of channel program segments

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · CVSS 9.3 Critical · fixed in a1625f66eaa1200068a0e2c05bc90e65182fc4e3 : patch Linux kernel as a priority.

Data as of 30 Oct 2026, 12:49 UTC

CVSS 3.1 base score
9.3Critical
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (Linux)CVSS 3.19.3
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Total control over the software or total information disclosure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in a1625f66eaa1200068a0e2c05bc90e65182fc4e3, 5405c90d6a47b3014e74ee0618a162449abbbc93, 15fb4559a7fdf0b8725e433a71cfd03a1313a48b +3
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 26 Aug 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: 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 30 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 0a19e61e6d4c6192077ead760ba0a2d350987d4c, < a1625f66eaa1200068a0e2c05bc90e65182fc4e3
Fixed in
  • a1625f66eaa1200068a0e2c05bc90e65182fc4e3
LinuxLinuxAffected
  • ≥ 0a19e61e6d4c6192077ead760ba0a2d350987d4c, < 5405c90d6a47b3014e74ee0618a162449abbbc93
Fixed in
  • 5405c90d6a47b3014e74ee0618a162449abbbc93
LinuxLinuxAffected
  • ≥ 0a19e61e6d4c6192077ead760ba0a2d350987d4c, < 15fb4559a7fdf0b8725e433a71cfd03a1313a48b
Fixed in
  • 15fb4559a7fdf0b8725e433a71cfd03a1313a48b
LinuxLinuxAffected
  • ≥ 0a19e61e6d4c6192077ead760ba0a2d350987d4c, < 06f4d6e5a8af6c2072e8cd39dbc512c683ca7fb2
Fixed in
  • 06f4d6e5a8af6c2072e8cd39dbc512c683ca7fb2
LinuxLinuxAffected
  • ≥ 0a19e61e6d4c6192077ead760ba0a2d350987d4c, < 4ee94790490ae8dcc97df8597f07836c8a81bbcf
Fixed in
  • 4ee94790490ae8dcc97df8597f07836c8a81bbcf
LinuxLinuxAffected
  • ≥ 0a19e61e6d4c6192077ead760ba0a2d350987d4c, < 2ce00bb19db13606cda79f4b7aae4d9775de3096
Fixed in
  • 2ce00bb19db13606cda79f4b7aae4d9775de3096

Description

In the Linux kernel, the following vulnerability has been resolved: s390/vfio_ccw: Limit the number of channel program segments The processing of channel programs, and the CCWs within them, is done recursively. As such, there is an arbitrary (but not architectural) limit to the number of CCWs that can exist in a single channel program. The vfio-ccw logic breaks these channel programs into segments whenever it encounters a Transfer-In-Channel (TIC) CCW, and the combined number of segments count towards the global limit. Impose an equivalent limit to the number of segments until such logic can be made non-recursive.

References

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