CVE-2026-80554
Published 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.
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References
Other References
https://git.kernel.org/stable/c/06f4d6e5a8af6c2072e8cd39dbc512c683ca7fb2
https://git.kernel.org/stable/c/15fb4559a7fdf0b8725e433a71cfd03a1313a48b
https://git.kernel.org/stable/c/4ee94790490ae8dcc97df8597f07836c8a81bbcf
https://git.kernel.org/stable/c/5405c90d6a47b3014e74ee0618a162449abbbc93
https://git.kernel.org/stable/c/a1625f66eaa1200068a0e2c05bc90e65182fc4e3
Frequently Asked Questions
What is CVE-2026-80554? +
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.
How do I check if I'm vulnerable to CVE-2026-80554? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.