CVE-2025-49179 | Xorg-x11-server-xwayland: xorg-x11-server: tigervnc: integer overflow in x record extension

A flaw was found in the X Record extension. The RecordSanityCheckRegisterClients function does not check for an integer overflow when computing request length, which allows a client to bypass length checks.

Published: 2025-06-17 Last update: 2026-06-30 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2025-49179 is rated Low Risk (36.1/100): CVSS High severity, with low exploitation likelihood (EPSS 0.28%). Mandatory action: 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-2025-49179

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 2026-06-15 0.15% 0.28% +0.12%
2 2026-04-13 0.05% 0.15% +0.10%
3 2026-03-03 0.05%

Full EPSS history (4 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-49179

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.3 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/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:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
1.8 5.5 [email protected]

Weakness enumeration for CVE-2025-49179

OS Trackers for CVE-2025-49179

vendor priority summary link
alpine CVE-2025-49179: 2 source package rows (xorg-server, xwayland); 4 state rows across 2 repos (3.22-community, edge-community); fixed 4, open 0. https://security.alpinelinux.org/vuln/CVE-2025-49179
debian not yet assigned CVE-2025-49179 not yet assigned priority: Debian including 2 source packages (xorg-server, xwayland), 9 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 7, open 2. https://security-tracker.debian.org/tracker/CVE-2025-49179
redhat high https://access.redhat.com/security/cve/CVE-2025-49179
suse high CVE-2025-49179 severity important: SUSE including 319 source package names (21.1-46.1:xorg-x11-server-21.1.11-150600.5.12.1, 21.1-46.1:xorg-x11-server-Xvfb-21.1.11-150600.5.12.1, …), 405 product×package rows across 56 product lines (Container suse/kiosk/xorg, Image SLES15-SP4-SAP, … (56 product lines)): Known Affected 231, Fixed 174. https://www.suse.com/security/cve/CVE-2025-49179/
ubuntu medium CVE-2025-49179 medium priority: Ubuntu including 7 source packages (xorg, xorg-hwe-16.04, …), 53 status rows across 10 suites (bionic, focal, jammy, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 20, released 17, not-affected 13, needs-triage 3. https://ubuntu.com/security/CVE-2025-49179

Affected software / configurations for CVE-2025-49179

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2025-49179

URL Tags
https://access.redhat.com/errata/RHSA-2025:10258
https://access.redhat.com/errata/RHSA-2025:10342
https://access.redhat.com/errata/RHSA-2025:10343
https://access.redhat.com/errata/RHSA-2025:10344
https://access.redhat.com/errata/RHSA-2025:10346
https://access.redhat.com/errata/RHSA-2025:10347
https://access.redhat.com/errata/RHSA-2025:10348
https://access.redhat.com/errata/RHSA-2025:10349
https://access.redhat.com/errata/RHSA-2025:10350
https://access.redhat.com/errata/RHSA-2025:10351
https://access.redhat.com/errata/RHSA-2025:10352
https://access.redhat.com/errata/RHSA-2025:10355
https://access.redhat.com/errata/RHSA-2025:10356
https://access.redhat.com/errata/RHSA-2025:10360
https://access.redhat.com/errata/RHSA-2025:10370
https://access.redhat.com/errata/RHSA-2025:10374
https://access.redhat.com/errata/RHSA-2025:10375
https://access.redhat.com/errata/RHSA-2025:10376
https://access.redhat.com/errata/RHSA-2025:10377
https://access.redhat.com/errata/RHSA-2025:10378
https://access.redhat.com/errata/RHSA-2025:10381
https://access.redhat.com/errata/RHSA-2025:10410
https://access.redhat.com/errata/RHSA-2025:9303
https://access.redhat.com/errata/RHSA-2025:9304
https://access.redhat.com/errata/RHSA-2025:9305
https://access.redhat.com/errata/RHSA-2025:9306
https://access.redhat.com/errata/RHSA-2025:9392
https://access.redhat.com/errata/RHSA-2025:9964
https://access.redhat.com/security/cve/CVE-2025-49179
https://bugzilla.redhat.com/show_bug.cgi?id=2369978
https://gitlab.freedesktop.org/xorg/xserver/-/commit/2bde9ca49a8fd9a1e6697d5e7ef837870d66f5d4
https://www.x.org/wiki/Development/Security/
https://lists.debian.org/debian-lts-announce/2025/06/msg00028.html
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