CVE Vulnerabilities

CVE-2025-26601

Use After Free

Published: Feb 25, 2025 | Modified: Mar 17, 2025
CVSS 3.x
N/A
Source:
NVD
CVSS 2.x
RedHat/V2
RedHat/V3
7.8 IMPORTANT
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Ubuntu
MEDIUM

A use-after-free flaw was found in X.Org and Xwayland. When changing an alarm, the values of the change mask are evaluated one after the other, changing the trigger values as requested, and eventually, SyncInitTrigger() is called. If one of the changes triggers an error, the function will return early, not adding the new sync object, possibly causing a use-after-free when the alarm eventually triggers.

Weakness 

Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code.

Affected Software 

Name Vendor Start Version End Version
Tigervnc Tigervnc - (including) - (including)
Red Hat Enterprise Linux 7 Extended Lifecycle Support RedHat tigervnc-0:1.8.0-36.el7_9 *
Red Hat Enterprise Linux 7 Extended Lifecycle Support RedHat xorg-x11-server-0:1.20.4-30.el7_9 *
Red Hat Enterprise Linux 8 RedHat tigervnc-0:1.13.1-15.el8_10 *
Red Hat Enterprise Linux 8.2 Advanced Update Support RedHat tigervnc-0:1.9.0-15.el8_2.13 *
Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support RedHat tigervnc-0:1.11.0-8.el8_4.12 *
Red Hat Enterprise Linux 8.4 Telecommunications Update Service RedHat tigervnc-0:1.11.0-8.el8_4.12 *
Red Hat Enterprise Linux 8.4 Update Services for SAP Solutions RedHat tigervnc-0:1.11.0-8.el8_4.12 *
Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support RedHat tigervnc-0:1.12.0-6.el8_6.13 *
Red Hat Enterprise Linux 8.6 Telecommunications Update Service RedHat tigervnc-0:1.12.0-6.el8_6.13 *
Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions RedHat tigervnc-0:1.12.0-6.el8_6.13 *
Red Hat Enterprise Linux 8.8 Extended Update Support RedHat tigervnc-0:1.12.0-15.el8_8.12 *
Red Hat Enterprise Linux 9 RedHat tigervnc-0:1.14.1-1.el9_5.1 *
Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions RedHat tigervnc-0:1.11.0-22.el9_0.13 *
Red Hat Enterprise Linux 9.2 Extended Update Support RedHat tigervnc-0:1.12.0-14.el9_2.10 *
Red Hat Enterprise Linux 9.4 Extended Update Support RedHat tigervnc-0:1.13.1-8.el9_4.5 *
Xorg-server Ubuntu devel *
Xorg-server Ubuntu esm-infra/bionic *
Xorg-server Ubuntu esm-infra/xenial *
Xorg-server Ubuntu focal *
Xorg-server Ubuntu jammy *
Xorg-server Ubuntu noble *
Xorg-server Ubuntu oracular *
Xorg-server Ubuntu upstream *
Xorg-server-hwe-16.04 Ubuntu esm-infra/xenial *
Xorg-server-hwe-18.04 Ubuntu esm-infra/bionic *
Xwayland Ubuntu devel *
Xwayland Ubuntu jammy *
Xwayland Ubuntu noble *
Xwayland Ubuntu oracular *
Xwayland Ubuntu upstream *

Extended Description 

The use of previously-freed memory can have any number of adverse consequences, ranging from the corruption of valid data to the execution of arbitrary code, depending on the instantiation and timing of the flaw. The simplest way data corruption may occur involves the system’s reuse of the freed memory. Use-after-free errors have two common and sometimes overlapping causes:

In this scenario, the memory in question is allocated to another pointer validly at some point after it has been freed. The original pointer to the freed memory is used again and points to somewhere within the new allocation. As the data is changed, it corrupts the validly used memory; this induces undefined behavior in the process. If the newly allocated data happens to hold a class, in C++ for example, various function pointers may be scattered within the heap data. If one of these function pointers is overwritten with an address to valid shellcode, execution of arbitrary code can be achieved.

Potential Mitigations 

References