CVE-2025-26596

HIGHNVD 7.87.8—

7.8

A heap overflow flaw was found in X.Org and Xwayland. The computation of the length in XkbSizeKeySyms() differs from what is written in XkbWriteKeySyms(), which may lead to a heap-based buffer overflow.

CVSS v3: 7.8
EG Score: 7.8(medium)
EPSS: 30.7%
KEV: Not listed

Published

February 25, 2025

Last Modified

April 6, 2026

References (18)

secalert@redhathttps://access.redhat.com/errata/RHSA-2025:2500
secalert@redhathttps://access.redhat.com/errata/RHSA-2025:2502
secalert@redhathttps://access.redhat.com/errata/RHSA-2025:2861
secalert@redhathttps://access.redhat.com/errata/RHSA-2025:2862
secalert@redhathttps://access.redhat.com/errata/RHSA-2025:2865
secalert@redhathttps://access.redhat.com/errata/RHSA-2025:2866
secalert@redhathttps://access.redhat.com/errata/RHSA-2025:2873
secalert@redhathttps://access.redhat.com/errata/RHSA-2025:2874
secalert@redhathttps://access.redhat.com/errata/RHSA-2025:2875
secalert@redhathttps://access.redhat.com/errata/RHSA-2025:2879
secalert@redhathttps://access.redhat.com/errata/RHSA-2025:2880
secalert@redhathttps://access.redhat.com/errata/RHSA-2025:3976
secalert@redhathttps://access.redhat.com/errata/RHSA-2025:7163
secalert@redhathttps://access.redhat.com/errata/RHSA-2025:7165
secalert@redhathttps://access.redhat.com/errata/RHSA-2025:7458

Vendor Advisories for CVE-2025-26596(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

CVE-2025-26596
Microsoft Security Response Center (MSRC)High
Xorg: xwayland: heap overflow in xkbwritekeysyms()

Patch Availability(18)

Vendor / Ecosystem	Fixed in / Patch	Released	Source
ubuntu	xwayland (2:24.1.2-1ubuntu0.4) @ oracular	2026-05-21	ubuntu
ubuntu	xwayland-hwe-18.04 (2:1.20.8-2ubuntu2.2~18.04.11+esm4) @ bionic	2026-05-21	ubuntu
ubuntu	xwayland-hwe-16.04 (2:1.19.6-1ubuntu4.1~16.04.6+esm7) @ xenial	2026-05-21	ubuntu
redhat	xorg-x11-server-Xwayland-0:24.1.5-3.el10_0	2025-05-13	redhat
redhat	xorg-x11-server-0:1.20.11-28.el9_6	2025-05-13	redhat
redhat	xorg-x11-server-Xwayland-0:23.2.7-3.el9_6	2025-05-13	redhat
redhat	tigervnc-0:1.1.0-25.el6_10	2025-04-17	redhat
redhat	tigervnc-0:1.12.0-6.el8_6.13	2025-03-17	redhat
redhat	tigervnc-0:1.12.0-15.el8_8.12	2025-03-17	redhat
redhat	tigervnc-0:1.13.1-8.el9_4.5	2025-03-17	redhat
redhat	tigervnc-0:1.8.0-36.el7_9	2025-03-17	redhat
redhat	tigervnc-0:1.11.0-8.el8_4.12	2025-03-17	redhat
redhat	tigervnc-0:1.12.0-14.el9_2.10	2025-03-17	redhat
redhat	tigervnc-0:1.9.0-15.el8_2.13	2025-03-17	redhat
redhat	tigervnc-0:1.11.0-22.el9_0.13	2025-03-17	redhat
redhat	xorg-x11-server-0:1.20.4-30.el7_9	2025-03-17	redhat
redhat	tigervnc-0:1.13.1-15.el8_10	2025-03-10	redhat
redhat	tigervnc-0:1.14.1-1.el9_5.1	2025-03-10	redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

CWE-787Out-of-bounds Write

Additional Vendor Advisories

(18)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 14× in last 7d / 62× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

2026-06-23 21:32 UTCEPSS rescore
2026-06-23 21:32 UTCEPSS rescore
2026-06-22 14:25 UTCEPSS rescore
2026-06-22 14:25 UTCEPSS rescore
2026-06-22 01:37 UTCOSV refresh
2026-06-21 14:56 UTCEPSS rescore
2026-06-21 14:56 UTCEPSS rescore
2026-06-21 01:59 UTCEPSS rescore
2026-06-21 01:59 UTCEPSS rescore
2026-06-19 19:25 UTCEPSS rescore
2026-06-19 19:25 UTCEPSS rescore
2026-06-18 17:52 UTCEPSS rescore
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2026-06-17 17:52 UTCEPSS rescore
2026-06-16 17:52 UTCEPSS rescore
2026-06-16 17:52 UTCEPSS rescore
2026-06-15 17:48 UTCEPSS rescore
2026-06-14 23:17 UTCEPSS rescore
2026-06-13 22:59 UTCEPSS rescore
2026-06-12 23:11 UTCEPSS rescore
2026-06-11 13:59 UTCEPSS rescore
2026-06-10 22:18 UTCEPSS rescore
2026-06-10 13:22 UTCEPSS rescore
2026-06-08 14:16 UTCEPSS rescore
2026-06-08 14:16 UTCEPSS rescore

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2026-06-07 15:24 UTCEPSS rescore
2026-06-07 15:24 UTCEPSS rescore
2026-06-06 13:47 UTCEPSS rescore
2026-06-06 13:47 UTCEPSS rescore
2026-06-05 22:46 UTCEPSS rescore
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2026-06-05 06:10 UTCEPSS rescore
2026-06-05 06:10 UTCEPSS rescore
2026-06-04 13:11 UTCEPSS rescore
2026-06-04 13:11 UTCEPSS rescore
2026-06-03 18:09 UTCOSV refresh
2026-06-02 20:12 UTCEPSS rescore
2026-06-02 20:12 UTCEPSS rescore
2026-06-01 13:51 UTCEPSS rescore
2026-06-01 13:51 UTCEPSS rescore
2026-05-31 22:30 UTCEPSS rescore
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2026-05-31 00:16 UTCEPSS rescore
2026-05-31 00:16 UTCEPSS rescore
2026-05-29 13:44 UTCEPSS rescore
2026-05-28 13:44 UTCEPSS rescore
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2026-05-27 13:40 UTCEPSS rescore
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2026-05-26 13:43 UTCEPSS rescore
2026-05-26 13:43 UTCEPSS rescore
2026-05-26 13:43 UTCEPSS rescore
2026-05-26 13:43 UTCEPSS rescore
2026-05-26 07:18 UTCEPSS rescore
2026-05-26 07:18 UTCEPSS rescore
2026-05-26 07:18 UTCEPSS rescore
2026-05-26 07:18 UTCEPSS rescore
2026-05-23 15:20 UTCEPSS rescore
2026-05-22 21:16 UTCEPSS rescore
2026-05-22 21:16 UTCEPSS rescore
2026-05-21 22:42 UTCEPSS rescore
2026-05-21 17:18 UTCEG score recompute
2026-05-21 17:18 UTCVendor advisory
2026-05-21 17:18 UTCGHSA enrichment
2026-05-20 22:37 UTCEPSS rescore
2026-05-20 22:37 UTCEPSS rescore
2026-05-20 22:37 UTCEPSS rescore
2026-05-20 22:37 UTCEPSS rescore
2026-05-20 22:37 UTCEPSS rescore
2026-05-20 22:37 UTCEPSS rescore
2026-05-20 11:21 UTCEPSS rescore
2026-05-20 11:21 UTCEPSS rescore
2026-05-20 11:21 UTCEPSS rescore
2026-05-20 11:21 UTCEPSS rescore
2026-05-20 11:21 UTCEPSS rescore
2026-05-18 21:31 UTCEPSS rescore

Frequently asked(5)

What is CVE-2025-26596?

CVE-2025-26596 is a high vulnerability published on February 25, 2025. A heap overflow flaw was found in X.Org and Xwayland. The computation of the length in XkbSizeKeySyms() differs from what is written in XkbWriteKeySyms(), which may lead to a heap-based buffer overflow.

When was CVE-2025-26596 disclosed?

CVE-2025-26596 was first published in the National Vulnerability Database on February 25, 2025, with the most recent update on April 6, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2025-26596 actively exploited?

CVE-2025-26596 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 30.7% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2025-26596?

CVE-2025-26596 has a CVSS v3 base score of 7.8 (NVD).

How do I remediate CVE-2025-26596?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2025-26596, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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CVE-2025-26596

Published

Last Modified

References (18)

Vendor Advisories for CVE-2025-26596(1)

Patch Availability(18)

Weakness Classification(1)

Additional Vendor Advisories

Data Freshness Timeline

Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2025-26596?

Same vendor

Same CWE

CVE-2025-26596

📅 Published

🔄 Last Modified

🔗 References (18)

📣 Vendor Advisories for CVE-2025-26596(1)

Patch Availability(18)

Weakness Classification(1)

Additional Vendor Advisories

Data Freshness Timeline

❓ Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2025-26596?

🔗 Related CVEs(same vendor + same CWE)

Same vendor

Same CWE

Published

Last Modified

References (18)

Vendor Advisories for CVE-2025-26596(1)

Frequently asked(5)

Related CVEs(same vendor + same CWE)