CVE-2026-80550

7.9 HIGH 0.1% exploit odds No fix listed Other OS & kernel

What it is

In the Linux kernel, the following vulnerability has been resolved: s390/vfio_ccw: Fix out of bounds check on CCW array The routine ccwchain_calc_length() counts the number of channel command words (CCWs) that are chained together in a single channel program, and rejects anything larger than CCWCHAIN_LEN_MAX (256) CCWs. The loop itself is "do..while (count < 257)", and while the logic in is_cpa_within_range() correctly adjusts between the 0-index array of CCWs and the count of CCWs starting at 1, this means it would look at a possible 257th CCW before ending the loop and (correctly) returning an error. Fix this by restructuring the loop to break as soon as 256 CCWs (thus indexes 0-255) are examined, without looking at memory outside the range.

At a glance

Exploitability: Can be exploited locally on the machine without logging in. High risk of data exposure.
Exploit odds: 0.1% chance of exploitation in the next 30 days (EPSS).
Fix: No patch or advisory is linked yet. Look at mitigations or restrict exposure.

Timeline

2026-08-26 15:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-10-16 20:17 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.1% in the next 30 days (EPSS).
Severity: 7.9 HIGH (CVSS).
Fix: none linked yet, which raises it.

Details

Published: 2026-08-26 15:17 UTC
Last modified: 2026-10-16 20:17 UTC
Exploit probability: 0.1% · EPSS, next 30 days
Record status: Received

Attack profile CVSS 3.1 · 7.9

Attack vector: Local
Complexity: Low
Privileges needed: None
User interaction: None
Scope: Changed
Confidentiality: High
Integrity: None
Availability: Low

Raw vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:L

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-80550.md and follow it. Check whether this project is affected by CVE-2026-80550. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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References

NVD record · CVE.org record