CVE-2026-80554

s390/vfio_ccw: Limit the number of channel program segments

State: Published
Severity: 9.3 Critical
Published: Aug 26, 2026
Updated: Oct 30, 2026
Reserved: Aug 26, 2026

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.

Scores

CVSS	Score	Vector	Source
3.1	9.3 Critical	CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H	Linux

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
LinuxLinux	0a19e61e6d4c6192077ead760ba0a2d350987d4c to before 2ce00bb19db13606cda79f4b7aae4d9775de3096Affected 0a19e61e6d4c6192077ead760ba0a2d350987d4c to before 15fb4559a7fdf0b8725e433a71cfd03a1313a48bAffected 0a19e61e6d4c6192077ead760ba0a2d350987d4c to before a1625f66eaa1200068a0e2c05bc90e65182fc4e3Affected 0a19e61e6d4c6192077ead760ba0a2d350987d4c to before 06f4d6e5a8af6c2072e8cd39dbc512c683ca7fb2Affected 0a19e61e6d4c6192077ead760ba0a2d350987d4c to before 4ee94790490ae8dcc97df8597f07836c8a81bbcfAffected 0a19e61e6d4c6192077ead760ba0a2d350987d4c to before 5405c90d6a47b3014e74ee0618a162449abbbc93Affected
LinuxLinux	4.12Affected before 4.12Not affected 6.1.191 through 6.1.Not affected 6.6.153 through 6.6.Not affected 6.12.105 through 6.12.Not affected 6.18.46 through 6.18.Not affected 7.1.10 through 7.1.*Not affected 7.2 and laterNot affected

Product

Versions

LinuxLinux

0a19e61e6d4c6192077ead760ba0a2d350987d4c to before 2ce00bb19db13606cda79f4b7aae4d9775de3096Affected
0a19e61e6d4c6192077ead760ba0a2d350987d4c to before 15fb4559a7fdf0b8725e433a71cfd03a1313a48bAffected
0a19e61e6d4c6192077ead760ba0a2d350987d4c to before a1625f66eaa1200068a0e2c05bc90e65182fc4e3Affected
0a19e61e6d4c6192077ead760ba0a2d350987d4c to before 06f4d6e5a8af6c2072e8cd39dbc512c683ca7fb2Affected
0a19e61e6d4c6192077ead760ba0a2d350987d4c to before 4ee94790490ae8dcc97df8597f07836c8a81bbcfAffected
0a19e61e6d4c6192077ead760ba0a2d350987d4c to before 5405c90d6a47b3014e74ee0618a162449abbbc93Affected

LinuxLinux

4.12Affected
before 4.12Not affected
6.1.191 through 6.1.*Not affected
6.6.153 through 6.6.*Not affected
6.12.105 through 6.12.*Not affected
6.18.46 through 6.18.*Not affected
7.1.10 through 7.1.*Not affected
7.2 and laterNot affected

References

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