CVE-2025-26595
published 2025-02-25CVE-2025-26595: 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…
PriorityP344high7.8CVSS 3.1
AVLACLPRLUINSUCHIHAH
EPSS
0.40%
32.3th percentile
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.
Affected
16 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | xorg-server | < xorg-server 2:21.1.7-3+deb12u9 (bookworm) | xorg-server 2:21.1.7-3+deb12u9 (bookworm) |
| debian | xwayland | < xorg-server 2:21.1.7-3+deb12u9 (bookworm) | xorg-server 2:21.1.7-3+deb12u9 (bookworm) |
| msrc | azl3_xorg-x11-server-xwayland_24.1.1-3_on_azure_linux_3.0 | — | — |
| msrc | azl3_xorg-x11-server-xwayland_24.1.6-1_on_azure_linux_3.0 | — | — |
| msrc | cbl2_xorg-x11-server_1.20.10-15_on_cbl_mariner_2.0 | — | — |
| redhat | enterprise_linux | — | — |
| redhat | enterprise_linux | — | — |
| redhat | enterprise_linux | — | — |
| x.org | x_server | < 21.1.16 | 21.1.16 |
| x.org | xorg-server | >= 0 < 2:1.20.11-1+deb11u15 | 2:1.20.11-1+deb11u15 |
| x.org | xorg-server | >= 0 < 2:21.1.7-3+deb12u9 | 2:21.1.7-3+deb12u9 |
| x.org | xorg-server | >= 0 < 2:21.1.16-1 | 2:21.1.16-1 |
| x.org | xorg-server | >= 0 < 2:21.1.16-1 | 2:21.1.16-1 |
| x.org | xwayland | < 24.1.6 | 24.1.6 |
| x.org | xwayland | >= 0 < 2:24.1.6-1 | 2:24.1.6-1 |
| x.org | xwayland | >= 0 < 2:24.1.6-1 | 2:24.1.6-1 |
CVSS provenance
nvdv3.17.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
osv7.8HIGH
vendor_debian7.8HIGH
vendor_msrc7.8HIGH
vendor_redhat7.8HIGH
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Ubuntu
X.Org X Server regression
vendor_ubuntu·2025-03-17
CVE-2025-26598 X.Org X Server regression
Title: X.Org X Server regression
Summary: Several security issues were fixed in X.Org X Server.
USN-7299-2 fix vulnerabilities in X.Org X Server. This fix caused
a regression in Ubuntu 16.04 LTS and Ubuntu 18.04 LTS. This update
fix the regression and re-apply the fix for the CVE listed.
We apologize for the inconvenience.
Original advisory details:
Jan-Niklas Sohn discovered that the X.Org X Server incorrectly handled
certain memory operations. An attacker could use these issues to cause the
X Server to crash, leading to a denial of service, or possibly execute
arbitrary code.
Instructions: After a standard system update you need to reboot your computer to make all
the necessary changes.
Ubuntu
X.Org X Server vulnerabilities
vendor_ubuntu·2025-03-10
CVE-2025-26594 X.Org X Server vulnerabilities
Title: X.Org X Server vulnerabilities
Summary: Several security issues were fixed in X.Org X Server.
USN-7299-1 fixed several vulnerabilities in X.Org. This update provides
the corresponding update for Ubuntu 16.04 LTS and Ubuntu 18.04 LTS.
Original advisory details:
Jan-Niklas Sohn discovered that the X.Org X Server incorrectly handled
certain memory operations. An attacker could use these issues to cause the
X Server to crash, leading to a denial of service, or possibly execute
arbitrary code.
Instructions: After a standard system update you need to reboot your computer to make all
the necessary changes.
Red Hat
Xorg: xwayland: Buffer overflow in XkbVModMaskText()
vendor_redhat·2025-02-25·CVSS 7.8
CVE-2025-26595 [HIGH] CWE-121 Xorg: xwayland: Buffer overflow in XkbVModMaskText()
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.
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.
Statement: Xorg server does not run with root privileges in Red Hat Enterprise Linux 8 and 9, therefore, Red Hat Enterprise Linux 8 and 9 have been rated with a Moder
BSD
OpenBSD 7.5 Errata 018: SECURITY FIX
bsd_advisories·2025-02-25·CVSS 7.8
CVE-2025-26594 [HIGH] OpenBSD 7.5 Errata 018: SECURITY FIX
OpenBSD 7.5 Errata 018: SECURITY FIX
018: SECURITY FIX: February 25, 2025
All architectures Multiple X server issues. CVE-2025-26594 CVE-2025-26595 CVE-2025-26596 CVE-2025-26597 CVE-2025-26598 CVE-2025-26599 CVE-2025-26600 CVE-2025-26601
Ubuntu
X.Org X Server vulnerabilities
vendor_ubuntu·2025-02-25
CVE-2025-26595 X.Org X Server vulnerabilities
Title: X.Org X Server vulnerabilities
Summary: Several security issues were fixed in X.Org X Server.
Jan-Niklas Sohn discovered that the X.Org X Server incorrectly handled
certain memory operations. An attacker could use these issues to cause the
X Server to crash, leading to a denial of service, or possibly execute
arbitrary code.
Instructions: After a standard system update you need to reboot your computer to make all
the necessary changes.
Microsoft
Xorg: xwayland: buffer overflow in xkbvmodmasktext()
vendor_msrc·2025-02-11·CVSS 7.8
CVE-2025-26595 [HIGH] CWE-121 Xorg: xwayland: buffer overflow in xkbvmodmasktext()
Xorg: xwayland: buffer overflow in xkbvmodmasktext()
FAQ: Is Azure Linux the only Microsoft product that includes this open-source library and is therefore potentially affected by this vulnerability?
One of the main benefits to our customers who choose to use the Azure Linux distro is the commitment to keep it up to date with the most recent and most secure versions of the open source libraries with which the distro is composed. Microsoft is committed to transparency in this work which is why we began publishing CSAF/VEX in October 2025. See this blog post for more information. If impact to additional products is identified, we will update the CVE to reflect this.
Mariner: Mariner
redhat: redhat
Customer Action Required: Yes
Remediation: CBL-Mariner Releases
Reference: https://learn.
Debian
CVE-2025-26595: xorg-server - A buffer overflow flaw was found in X.Org and Xwayland. The code in XkbVModMaskT...
vendor_debian·2025·CVSS 7.8
CVE-2025-26595 [HIGH] CVE-2025-26595: xorg-server - A buffer overflow flaw was found in X.Org and Xwayland. The code in XkbVModMaskT...
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.
Scope: local
bookworm: resolved (fixed in 2:21.1.7-3+deb12u9)
bullseye: resolved (fixed in 2:1.20.11-1+deb11u15)
forky: resolved (fixed in 2:21.1.16-1)
sid: resolved (fixed in 2:21.1.16-1)
trixie: resolved (fixed in 2:21.1.16-1)
VulDB
Red Hat Enterprise Linux 6/7/8/9 X.org X11 Server/TigerVNC XkbVModMaskText stack-based overflow (EUVD-2025-5372 / Nessus ID 216902)
vuldb·2026-06-06·CVSS 7.8
CVE-2025-26595 [HIGH] Red Hat Enterprise Linux 6/7/8/9 X.org X11 Server/TigerVNC XkbVModMaskText stack-based overflow (EUVD-2025-5372 / Nessus ID 216902)
A vulnerability classified as critical was found in Red Hat Enterprise Linux 6/7/8/9. Affected by this issue is the function XkbVModMaskText of the component X.org X11 Server/TigerVNC. The manipulation results in stack-based buffer overflow.
This vulnerability is cataloged as CVE-2025-26595. The attack must be initiated from a local position. There is no exploit available.
GHSA
GHSA-hp9r-wcfh-72pr: A buffer overflow flaw was found in X
ghsa_unreviewed·2025-02-25
CVE-2025-26595 [HIGH] CWE-121 GHSA-hp9r-wcfh-72pr: A buffer overflow flaw was found in X
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.
OSV
CVE-2025-26595: A buffer overflow flaw was found in X
osv·2025-02-25·CVSS 7.8
CVE-2025-26595 [HIGH] CVE-2025-26595: A buffer overflow flaw was found in X
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.
No detection rules found.
No public exploits indexed.
https://access.redhat.com/errata/RHSA-2025:2500https://access.redhat.com/errata/RHSA-2025:2502https://access.redhat.com/errata/RHSA-2025:2861https://access.redhat.com/errata/RHSA-2025:2862https://access.redhat.com/errata/RHSA-2025:2865https://access.redhat.com/errata/RHSA-2025:2866https://access.redhat.com/errata/RHSA-2025:2873https://access.redhat.com/errata/RHSA-2025:2874https://access.redhat.com/errata/RHSA-2025:2875https://access.redhat.com/errata/RHSA-2025:2879https://access.redhat.com/errata/RHSA-2025:2880https://access.redhat.com/errata/RHSA-2025:3976https://access.redhat.com/errata/RHSA-2025:7163https://access.redhat.com/errata/RHSA-2025:7165https://access.redhat.com/errata/RHSA-2025:7458https://access.redhat.com/security/cve/CVE-2025-26595https://bugzilla.redhat.com/show_bug.cgi?id=2345257https://lists.debian.org/debian-lts-announce/2025/02/msg00036.html
2025-02-25
Published