CVE-2025-26595 | Xorg: xwayland: buffer overflow in xkbvmodmasktext()

A buffer overflow flaw was found in X.Org and Xwayland. The code in XkbVModMaskText() allocates a fixed-sized buffer on the stack and copies the names of the virtual modifiers to that buffer. The code fails to check the bounds of the buffer and would copy the data regardless of the size.

Published: 2025-02-25 Last update: 2026-04-06 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2025-26595 is rated Low Risk (33.2/100): CVSS High severity, with low exploitation likelihood (EPSS 0.02%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2025-26595

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-04-05 0.05% 0.02% -0.03%
2 2025-12-22 0.05% 0.05% +0.00%
3 2025-11-21 — 0.05% —

Full EPSS history (5 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-26595

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.8 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 5.9 [email protected]
7.8 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 5.9 [email protected]

Weakness enumeration for CVE-2025-26595

OS Trackers for CVE-2025-26595

vendor priority summary link
alpine — CVE-2025-26595: 2 source package rows (xorg-server, xwayland); 6 state rows across 3 repos (3.21-community, 3.22-community, edge-community); fixed 6, open 0. https://security.alpinelinux.org/vuln/CVE-2025-26595
debian not yet assigned CVE-2025-26595 not yet assigned priority: Debian including 2 source packages (xorg-server, xwayland), 9 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 8, open 1. https://security-tracker.debian.org/tracker/CVE-2025-26595
gentoo high CVE-2025-26595: 1 GLSA(s) (202506-04), 2 atom(s) (x11-base/xorg-server, x11-base/xwayland); latest impact high. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2025-26595
redhat high — https://access.redhat.com/security/cve/CVE-2025-26595
suse medium CVE-2025-26595 severity moderate: SUSE including 324 source package names (21:libxkbfile1-1.0.9-150000.3.3.1, 21:xorg-x11-server-21.1.11-150600.5.6.1, …), 576 product×package rows across 134 product lines (Container suse/kiosk/xorg, Image SLES12-SP5-Azure-SAP-BYOS, … (134 product lines)): Fixed 344, Known Affected 231, Known Not Affected 1. https://www.suse.com/security/cve/CVE-2025-26595/
ubuntu medium CVE-2025-26595 medium priority: Ubuntu including 7 source packages (xorg, xorg-hwe-16.04, …), 58 status rows across 10 suites (bionic, focal, jammy, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 25, released 17, not-affected 13, needs-triage 3. https://ubuntu.com/security/CVE-2025-26595

Affected software / configurations for CVE-2025-26595

Vendor Product Version Raw CPE
tigervnc tigervnc — cpe:2.3:a:tigervnc:tigervnc:-:*:*:*:*:*:*:*
x.org x_server < 21.1.16 cpe:2.3:a:x.org:x_server:*:*:*:*:*:*:*:*
x.org xwayland < 24.1.6 cpe:2.3:a:x.org:xwayland:*:*:*:*:*:*:*:*
redhat enterprise_linux 7.0 cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*
redhat enterprise_linux 8.0 cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
redhat enterprise_linux 9.0 cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*

References for CVE-2025-26595

URL Tags
https://access.redhat.com/errata/RHSA-2025:2500 Third Party Advisory
https://access.redhat.com/errata/RHSA-2025:2502 Third Party Advisory
https://access.redhat.com/errata/RHSA-2025:2861 Third Party Advisory
https://access.redhat.com/errata/RHSA-2025:2862 Third Party Advisory
https://access.redhat.com/errata/RHSA-2025:2865 Third Party Advisory
https://access.redhat.com/errata/RHSA-2025:2866 Third Party Advisory
https://access.redhat.com/errata/RHSA-2025:2873 Third Party Advisory
https://access.redhat.com/errata/RHSA-2025:2874 Third Party Advisory
https://access.redhat.com/errata/RHSA-2025:2875 Third Party Advisory
https://access.redhat.com/errata/RHSA-2025:2879 Third Party Advisory
https://access.redhat.com/errata/RHSA-2025:2880 Third Party Advisory
https://access.redhat.com/errata/RHSA-2025:3976
https://access.redhat.com/errata/RHSA-2025:7163
https://access.redhat.com/errata/RHSA-2025:7165
https://access.redhat.com/errata/RHSA-2025:7458
https://access.redhat.com/security/cve/CVE-2025-26595 Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2345257 Issue Tracking
https://lists.debian.org/debian-lts-announce/2025/02/msg00036.html
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