CVE-2025-49177
xorg-x11-server-Xwayland: xorg-x11-server: tigervnc: Data Leak in XFIXES Extension's XFixesSetClientDisconnectMode
Severity
ImportantRed Hat Product Security
CVSS 3.1
Review impact separately from score.
Published · June 17, 2025
Updated · June 30, 2026
Description
A flaw was found in the XFIXES extension. The XFixesSetClientDisconnectMode handler does not validate the request length, allowing a client to read unintended memory from previous requests.
Statement
This vulnerability is rated as an important severity because the flaw exists in the XFIXES extension, specifically in the XFixesSetClientDisconnectMode handler. The handler does not validate the request length field correctly, allowing a client to read beyond the intended bounds of the input buffer. This flaw can result in disclosure of uninitialized memory contents from prior operations, potentially exposing sensitive information from other clients or internal server state. While this issue primarily affects confidentiality, it may also impact availability if the invalid read leads to a crash.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
CVSS / CWE
CVSS 3.1 · 6.1CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:L
CWE-200 · Exposure of Sensitive Information to an Unauthorized Actor