CVE-2026-50256: Software Security Vulnerability Vulnerability

HIGH
Advisory Identifier: GHSA-7gx3-r5q9-6j33
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CVSS 7.8
CWE-121
Published
Advisory Summary

CVE-2026-50256 is a HIGH (CVSS 7.8) security vulnerability vulnerability (CWE-121: Stack-based Buffer Overflow) affecting Software libraries in the Maven ecosystem. The weakness occurs when 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).. Remediation is available in the latest vendor maintenance releases.

CVE-2026-50256 at a Glance

CVE Identifier CVE-2026-50256
GHSA Identifier GHSA-7gx3-r5q9-6j33
Severity HIGH
CVSS v3.1 Base Score 7.8
CWE Classification CWE-121: Stack-based Buffer Overflow
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 7.8

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).

Attack Vector Local (AV:L)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2026-50256

To remediate this vulnerability, upgrade all affected Software dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

mvn dependency:tree

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-50256, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree

Analyze the terminal output to locate any version of Software in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: The mvn dependency:tree command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-121: Stack-based Buffer Overflow, where 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). In Software, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

A stack-based buffer overflow flaw was found in the X.Org X server and Xwayland. A mismatch between the X server and the libXfont2 library's maximum font name length can cause a stack buffer overflow during font alias resolution. The server allocates a 256 byte stack buffer but libXfont2's alias target name length is 1024 bytes. A font alias name between 257 and 1023 bytes causes the X server to copy that name into the undersized stack buffer without further checks. This may be used to crash the server, or for privilege escalation if the X server runs as root.

References

access.redhat.com/errata/rhsa-2026:36... WEB
https://access.redhat.com/errata/RHSA-2026:36086
NVD — CVE-2026-50256 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-50256
access.redhat.com/errata/rhsa-2026:26... WEB
https://access.redhat.com/errata/RHSA-2026:26562
access.redhat.com/errata/rhsa-2026:38... WEB
https://access.redhat.com/errata/RHSA-2026:38502
access.redhat.com/errata/rhsa-2026:38... WEB
https://access.redhat.com/errata/RHSA-2026:38810
access.redhat.com/errata/rhsa-2026:46... WEB
https://access.redhat.com/errata/RHSA-2026:46377
access.redhat.com/errata/rhsa-2026:46... WEB
https://access.redhat.com/errata/RHSA-2026:46382
access.redhat.com/errata/rhsa-2026:46... WEB
https://access.redhat.com/errata/RHSA-2026:46385
access.redhat.com/errata/rhsa-2026:46... WEB
https://access.redhat.com/errata/RHSA-2026:46392
access.redhat.com/errata/rhsa-2026:46... WEB
https://access.redhat.com/errata/RHSA-2026:46456
access.redhat.com/errata/rhsa-2026:46... WEB
https://access.redhat.com/errata/RHSA-2026:46460
access.redhat.com/errata/rhsa-2026:46... WEB
https://access.redhat.com/errata/RHSA-2026:46473
access.redhat.com/errata/rhsa-2026:49... WEB
https://access.redhat.com/errata/RHSA-2026:49519
Software Security Information SECURITY
https://access.redhat.com/security/cve/CVE-2026-50256
bugzilla.redhat.com/show_bug.cgi WEB
https://bugzilla.redhat.com/show_bug.cgi?id=2485380
gitlab.freedesktop.org/xorg/xserver/-/comm... WEB
https://gitlab.freedesktop.org/xorg/xserver/-/commit/bb5158f962dc935e58ef8b4b5fcb31be201a6e07
lists.x.org/archives/xorg-annou... WEB
https://lists.x.org/archives/xorg-announce/2026-June/003702.html
redhat.atlassian.net/browse/psirtsupt-16... WEB
https://redhat.atlassian.net/browse/PSIRTSUPT-16950
Software Security Information SECURITY
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-50256.json
access.redhat.com/errata/rhsa-2026:26... WEB
https://access.redhat.com/errata/RHSA-2026:26566
access.redhat.com/errata/rhsa-2026:26... WEB
https://access.redhat.com/errata/RHSA-2026:26590
access.redhat.com/errata/rhsa-2026:26... WEB
https://access.redhat.com/errata/RHSA-2026:26610
access.redhat.com/errata/rhsa-2026:26... WEB
https://access.redhat.com/errata/RHSA-2026:26709
access.redhat.com/errata/rhsa-2026:28... WEB
https://access.redhat.com/errata/RHSA-2026:28923
access.redhat.com/errata/rhsa-2026:29... WEB
https://access.redhat.com/errata/RHSA-2026:29844
access.redhat.com/errata/rhsa-2026:36... WEB
https://access.redhat.com/errata/RHSA-2026:36083
access.redhat.com/errata/rhsa-2026:36... WEB
https://access.redhat.com/errata/RHSA-2026:36085
access.redhat.com/errata/rhsa-2026:36... WEB
https://access.redhat.com/errata/RHSA-2026:36087
access.redhat.com/errata/rhsa-2026:36... WEB
https://access.redhat.com/errata/RHSA-2026:36632
access.redhat.com/errata/rhsa-2026:36... WEB
https://access.redhat.com/errata/RHSA-2026:36633
access.redhat.com/errata/rhsa-2026:36... WEB
https://access.redhat.com/errata/RHSA-2026:36634
access.redhat.com/errata/rhsa-2026:36... WEB
https://access.redhat.com/errata/RHSA-2026:36768
access.redhat.com/errata/rhsa-2026:36... WEB
https://access.redhat.com/errata/RHSA-2026:36791
access.redhat.com/errata/rhsa-2026:36... WEB
https://access.redhat.com/errata/RHSA-2026:36792
access.redhat.com/errata/rhsa-2026:36... WEB
https://access.redhat.com/errata/RHSA-2026:36798

Frequently Asked Questions

What is CVE-2026-50256?
CVE-2026-50256 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-121: Stack-based Buffer Overflow.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-50256?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-50256?
CVE-2026-50256 has a CVSS v3.1 base score of 7.8 (HIGH) with vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2026-50256?
CVE-2026-50256 is classified under CWE-121: Stack-based Buffer Overflow (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).).
How can I check Maven dependencies for CVE-2026-50256?
Run the dependency tree command: 'mvn dependency:tree'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
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