CVE-2026-80550

HIGHPre-NVD 7.97.9—
EchelonGraph scoreHIGH confidence

Score 7.9 from GitHub Security Advisory (severity: HIGH) published 2026-08-27. a secondary CVSS source baseline 7.9; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 5 sources updated this week
7.9EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.9Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
7.9
EG Score
7.9(high)
EG Risk
40(Track)
EG Risk 40/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity79% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
3%
KEV
Not listed

Published

August 26, 2026

Last Modified

August 27, 2026

Advisory Details (8)

Auto-updated Aug 27, 2026
No patch confirmed yet.
generic

s390/vfio_ccw: Fix out of bounds check on CCW array - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/f20be33d093ce7630c17ff7ed93caf7eaf8ac1a3
generic

s390/vfio_ccw: Fix out of bounds check on CCW array - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/d5d096cd9369e986d4e5153baa86b8b35c283e09
generic

s390/vfio_ccw: Fix out of bounds check on CCW array - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/af3f80ca4c8b17f20f9e588def076288fdb49e65
generic

s390/vfio_ccw: Fix out of bounds check on CCW array - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/a005b7f1a491ffda61bff0fd0f6548f8986fb977
generic

s390/vfio_ccw: Fix out of bounds check on CCW array - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/907adc667d902fafbdb2d740d57b55bd025dc4cd
generic

s390/vfio_ccw: Fix out of bounds check on CCW array - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/4c2e1d359d7a2b82cdf3254e4e480af9417f99fb
generic

s390/vfio_ccw: Fix out of bounds check on CCW array - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/499a8a66b1598bfab97182aed15e0f1646074a3d
generic

s390/vfio_ccw: Fix out of bounds check on CCW array - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/0282fb1c4b638eecfe2cc558092c460911d8f7e2

Vendor Advisories for CVE-2026-80550(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Data Freshness Timeline

(refreshed 17× in last 7d / 17× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-08-30 02:38 UTCEG score recompute
  2. 2026-08-30 02:38 UTCGHSA enrichment
  3. 2026-08-30 01:22 UTCEPSS rescore
  4. 2026-08-29 15:24 UTCGHSA enrichment
  5. 2026-08-29 04:09 UTCEG score recompute
  6. 2026-08-29 04:09 UTCGHSA enrichment
  7. 2026-08-28 21:42 UTCEPSS rescore
  8. 2026-08-28 16:51 UTCGHSA enrichment
  9. 2026-08-28 05:32 UTCGHSA enrichment
  10. 2026-08-27 18:06 UTCEG score recompute
  11. 2026-08-27 18:06 UTCGHSA enrichment
  12. 2026-08-27 14:25 UTCEPSS rescore
  13. 2026-08-27 06:19 UTCEG score recompute▲ 7.90
  14. 2026-08-27 06:11 UTCMITRE cvelistV5CVSS v3 → 7.9 · severity → HIGH
  15. 2026-08-26 15:43 UTCNVD update
  16. 2026-08-26 14:42 UTCEG score recompute
  17. 2026-08-26 14:41 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-80550?
CVE-2026-80550 is a high vulnerability published on August 26, 2026. In the Linux kernel, the following vulnerability has been resolved: s390/vfio_ccw: Fix out of bounds check on CCW array The routine ccwchaincalclength() counts the number of channel command words (CCWs) that are chained together in a single channel program, and rejects anything larger than…
When was CVE-2026-80550 disclosed?
CVE-2026-80550 was first published in the National Vulnerability Database on August 26, 2026, with the most recent update on August 27, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-80550 actively exploited?
CVE-2026-80550 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 96.6% of all scored CVEs.
What is the CVSS score of CVE-2026-80550?
CVE-2026-80550 has a CVSS v3 base score of 7.9 (NVD).
How do I remediate CVE-2026-80550?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-80550, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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