CVE-2026-109833
Received Received - Intake

Out-of-Bounds Write in gnome-remote-desktop via VNC TLS

Publication date: 2026-10-13

Last updated on: 2026-10-13

Assigner: redhat-SADP

Description
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.

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Meta Information

Published
2026-10-13
Last Modified
2026-10-13
Generated
2026-10-13
AI Q&A
2026-10-13
EPSS Evaluated
N/A
NVD
CVE-2026-109833
EUVD
EUVD-2026-98479

Affected Vendors & Products

Showing 3 associated CPEs
Vendor Product Version / Range
Red Hat Red Hat Enterprise Linux 10 *
Red Hat Red Hat Enterprise Linux 8 *
Red Hat Red Hat Enterprise Linux 9 *

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-121 A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).

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Executive Summary

CVE-2026-109833 is a flaw in gnome-remote-desktop for Red Hat Enterprise Linux. It occurs in the VNC TLS read path where partial consumption of an internal peek buffer incorrectly moves remaining bytes into the caller's buffer instead of compacting the peek buffer. This causes an out-of-bounds write, leading to denial of service when an attacker triggers a peek/read size mismatch on an enabled VNC TLS listener.

Detection Guidance

To detect this vulnerability, check if gnome-remote-desktop is installed and running on affected RHEL versions (8, 9, or 10) with VNC TLS enabled. Use commands like 'rpm -q gnome-remote-desktop' to verify installation and 'systemctl status gnome-remote-desktop' to check service status. Inspect network traffic for VNC TLS connections on port 5900 or similar.

Impact Analysis

An attacker with network access to a vulnerable VNC TLS listener could cause a denial of service by triggering a buffer overflow. This may crash the gnome-remote-desktop service or the entire system. Confidentiality and integrity are not affected, but availability is compromised.

Mitigation Strategies

Disable the VNC service if not required using 'systemctl stop gnome-remote-desktop' and 'systemctl disable gnome-remote-desktop'. Restrict VNC listener access to trusted hosts via firewall rules (e.g., 'firewall-cmd --add-rich-rule="rule family="ipv4" source address="trusted_ip" service name="vnc-server" accept"'). Apply available patches from Red Hat immediately.

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