Out-of-bounds write in gnome-remote-desktop VNC TLS read path
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- High
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Deferred Red Hat: fix deferred
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-121 and the CVSS impact.
Summary
Red Hat Enterprise Linux 8 and 9 ship gnome-remote-desktop versions affected by this flaw, while Red Hat Enterprise Linux 10 is not affected. In the VNC TLS read path, partially consuming the internal peek buffer copies the remaining peeked bytes into the caller's buffer instead of compacting the peek buffer, which causes an out-of-bounds write (CWE-121). A remote attacker who can reach an enabled VNC TLS listener and trigger a peek and read size mismatch can crash the service, causing denial of service. CISA's KEV catalog does not list the flaw, and CISA's SSVC data records no exploitation.
Written with Claude Haiku 5.5 from the sources below · 2026-10-27
Description from the CNA
A flaw was found in gnome-remote-desktop as shipped in Red Hat Enterprise Linux. In the VNC TLS read path, partial consumption of the internal peek buffer incorrectly moves remaining peeked bytes into the caller-supplied buffer instead of compacting the peek buffer. A remote attacker who can reach an enabled VNC TLS listener and trigger a peek/read size mismatch can cause an out-of-bounds write, leading to denial of service.
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 |
|---|---|---|---|---|---|
| Red Hat | Red Hat Enterprise Linux 10 | — | — | Not affected | CNA |
| Red Hat | Red Hat Enterprise Linux 8 | — | — | No fix listed | CNA |
| Red Hat | Red Hat Enterprise Linux 9 | — | — | No fix listed | CNA |
Remediation
The sources list no fixed version for Red Hat Enterprise Linux 8 or 9. Red Hat lists no available remediation plan for these two products, and Red Hat Enterprise Linux 10 is not affected.
Written with Claude Haiku 5.5 from the sources below · 2026-10-27
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
Not affected: 1 product
- Red Hat Enterprise Linux 10
Timeline
- 2026-10-13 Threatist record created from CVE-2026-109833
- 2026-10-13 Alias added: GHSA-ww8j-g775-7xjg
- 2026-10-14 CISA SSVC decision points changed
- 2026-10-14 Priority changed: MEDIUM → LOW
References
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Sources
- CVE-2026-109833 · CVE Program
- CVE-2026-109833 · NVD
- FIRST EPSS
- GHSA-ww8j-g775-7xjg · GitHub Advisory Database · CC BY 4.0
- CVE-2026-109833 · 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