s390/vfio_ccw: Fix out of bounds check on CCW array
Key facts
- Attack vector
- Local
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · None · Low
- Fix status
- Partial Red Hat: 2 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 4.12 and later | 5.10.266, 5.15.217, 6.1.184, 6.6.153, 6.12.105, 6.18.46, 7.1.10, 7.2 | Patch available | CNA |
- Linux VendorLinux Affected 4.12 and later Fixed in 5.10.266, 5.15.217, 6.1.184, 6.6.153, 6.12.105, 6.18.46, 7.1.10, 7.2 Patch available CNA
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.10.266, 5.15.217, 6.1.184, 6.6.153, 6.12.105, 6.18.46, 7.1.10, 7.2
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
Not affected: 3 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
Timeline
- 2026-10-02 Threatist record created from CVE-2026-80550
- 2026-10-03 Alias added: GHSA-fw9c-wxjq-5w67
- 2026-10-18 CISA SSVC decision points changed
References
Other 8
- https://git.kernel.org/stable/c/0282fb1c4b638eecfe2cc558092c460911d8f7e2
- https://git.kernel.org/stable/c/907adc667d902fafbdb2d740d57b55bd025dc4cd
- https://git.kernel.org/stable/c/f20be33d093ce7630c17ff7ed93caf7eaf8ac1a3
- https://git.kernel.org/stable/c/af3f80ca4c8b17f20f9e588def076288fdb49e65
- https://git.kernel.org/stable/c/499a8a66b1598bfab97182aed15e0f1646074a3d
- https://git.kernel.org/stable/c/4c2e1d359d7a2b82cdf3254e4e480af9417f99fb
- https://git.kernel.org/stable/c/d5d096cd9369e986d4e5153baa86b8b35c283e09
- https://git.kernel.org/stable/c/a005b7f1a491ffda61bff0fd0f6548f8986fb977
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Sources
- CVE-2026-80550 · CVE Program
- CVE-2026-80550 · NVD
- FIRST EPSS
- GHSA-fw9c-wxjq-5w67 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-80550 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences