Integer underflow in clevis PKCS#11 socket handler crashes daemon
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- High
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-787 and the CVSS impact.
Summary
The clevis PKCS#11 pin in Red Hat Enterprise Linux 9 and 10 is affected. An integer underflow in the getpeername result handling causes an out-of-bounds write (CWE-787). A local user with low privileges can crash the clevis-pkcs11-afunix-socket-unlock daemon by connecting an AF_UNIX client to the data socket without a bound address. The crash is a denial of service that prevents LUKS disk decryption from completing during boot.
Written with Claude Haiku 5.5 from the sources below · 2026-10-30
Description from the CNA
A flaw was found in the clevis PKCS#11 pin. The clevis-pkcs11-afunix-socket-unlock daemon crashes when an AF_UNIX client connects to the data socket without a bound address, due to an integer underflow in the getpeername result handling. This causes a denial of service, preventing LUKS disk decryption from completing during boot.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- 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 |
|---|---|---|---|---|---|
| Red Hat | Red Hat Enterprise Linux 10 | — | — | No fix listed | CNA |
| Red Hat | Red Hat Enterprise Linux 7 | — | — | Not affected | CNA |
| Red Hat | Red Hat Enterprise Linux 8 | — | — | Not affected | CNA |
| Red Hat | Red Hat Enterprise Linux 9 | — | — | No fix listed | CNA |
| Red Hat | Red Hat OpenShift Container Platform 4 | — | — | Not affected | CNA |
| Red Hat | Red Hat OpenShift Container Platform 4 | — | — | Not affected | CNA |
| Red Hat | Red Hat OpenShift Container Platform 5 | — | — | Not affected | CNA |
- Red Hat Enterprise Linux 10 VendorRed Hat Affected — Fixed in — No fix listed CNA
- Red Hat Enterprise Linux 7 VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat Enterprise Linux 8 VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat Enterprise Linux 9 VendorRed Hat Affected — Fixed in — No fix listed CNA
- Red Hat OpenShift Container Platform 4 VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat OpenShift Container Platform 4 VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat OpenShift Container Platform 5 VendorRed Hat Affected — Fixed in — Not affected CNA
CPE names CNA · 6
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:/a:redhat:enterprise_linux:10 | 10 | — | Red Hat |
| cpe:/o:redhat:rhel_els:7 | 7 | — | Red Hat |
| cpe:/a:redhat:enterprise_linux:8 | 8 | — | Red Hat |
| cpe:/a:redhat:enterprise_linux:9 | 9 | — | Red Hat |
| cpe:/a:redhat:openshift:4 | 4 | — | Red Hat |
| cpe:/a:redhat:openshift:5 | 5 | — | Red Hat |
- cpe:/a:redhat:enterprise_linux:10 Versions 10 — ·Red Hat
- cpe:/o:redhat:rhel_els:7 Versions 7 — ·Red Hat
- cpe:/a:redhat:enterprise_linux:8 Versions 8 — ·Red Hat
- cpe:/a:redhat:enterprise_linux:9 Versions 9 — ·Red Hat
- cpe:/a:redhat:openshift:4 Versions 4 — ·Red Hat
- cpe:/a:redhat:openshift:5 Versions 5 — ·Red Hat
Remediation
No fixed version is listed for Red Hat Enterprise Linux 10 or 9. Red Hat Enterprise Linux 7 and 8 and Red Hat OpenShift Container Platform are not affected.
Written with Claude Haiku 5.5 from the sources below · 2026-10-30
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet |
| Red Hat Enterprise Linux 9 | Affected | No fix yet |
Not affected: 4 products
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat OpenShift Container Platform 4
- Red Hat OpenShift Container Platform 5
Timeline
- 2026-10-13 Threatist record created from CVE-2026-109976
- 2026-10-13 Alias added: GHSA-vqch-3qxf-26cw
- 2026-10-15 CISA SSVC decision points changed
- 2026-10-15 Priority changed: LOW → MEDIUM
- 2026-10-30 Affected versions changed · CNA
- 2026-10-30 Affected versions changed · Red Hat
References
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- TI-2018-16080 A code execution vulnerability exists in the Stapler web framework used by Jenkins 2.153… KEVCVSS 3.1CRITICAL 9.8
Sources
- CVE-2026-109976 · CVE Program
- CVE-2026-109976 · NVD
- FIRST EPSS
- GHSA-vqch-3qxf-26cw · GitHub Advisory Database · CC BY 4.0
- CVE-2026-109976 · 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