Heap overflow in spice-server GLZ dictionary restore path
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- High
- Impact type
- Code execution
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-190 and the CVSS impact.
Summary
Red Hat Enterprise Linux 6, 7 and 8 ship spice-server, which is affected. The GLZ encoder dictionary restore path truncates a size_t allocation size to int (CWE-190) when calling the malloc callback, causing a heap buffer overflow. A malicious authenticated SPICE client can trigger it during VM live migration by sending a crafted max_encoders value in migration data.
Written with Claude Haiku 5.5 from the sources below · 2026-10-28
Description from the CNA
A flaw was found in spice-server. The GLZ encoder dictionary restore path truncates a size_t allocation size to int when calling the malloc callback, allowing a malicious authenticated SPICE client during VM live migration to trigger a massive heap buffer overflow by sending a crafted max_encoders value in migration data.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
The sources list no fixed version for Red Hat Enterprise Linux 6, 7 or 8, and no planned fix for these products.
Written with Claude Haiku 5.5 from the sources below · 2026-10-28
Vendor assessments
Red Hat
Red Hat rating: Important. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 6 | Affected | No fix yet |
| Red Hat Enterprise Linux 7 | Affected | No fix yet |
| Red Hat Enterprise Linux 8 | Affected | No fix yet |
Timeline
- 2026-10-16 Threatist record created from CVE-2026-105959
- 2026-10-16 Affected versions changed · Red Hat
- 2026-10-16 CVSS score added · Red Hat
- 2026-10-16 Alias added: GHSA-m5f2-676c-jfj7
References
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Sources
- CVE-2026-105959 · CVE Program
- CVE-2026-105959 · NVD
- FIRST EPSS
- GHSA-m5f2-676c-jfj7 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-105959 · 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