CVE-2025-49794 | Libxml: heap use after free (uaf) leads to denial of service (dos)

A use-after-free vulnerability was found in libxml2. This issue occurs when parsing XPath elements under certain circumstances when the XML schematron has the <sch:name path="..."/> schema elements. This flaw allows a malicious actor to craft a malicious XML document used as input for libxml, resulting in the program's crash using libxml or other possible undefined behaviors.

Published: 2025-06-16 Last update: 2026-06-02 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2025-49794 is rated Moderate Risk (53.1/100): CVSS Critical severity, with low exploitation likelihood (EPSS 0.67%). Mandatory action: Review affected assets and schedule remediation.

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-2025-49794

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 0.45% 0.67% +0.22%
2 2026-04-12 0.06% 0.45% +0.39%
3 2026-01-27 0.06%

Full EPSS history (12 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-49794

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.1 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
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:N)
No account or special rights needed—anonymous or random user is enough.
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:N)
Doesn’t really leak secrets in a meaningful 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.
3.9 5.2 [email protected]

Weakness enumeration for CVE-2025-49794

GitHub Security Advisory for CVE-2025-49794

GHSA-qg4c-8pj4-qgw2 · Severity: critical — A use-after-free vulnerability was found in libxml2. This issue occurs when parsing XPath...

OS Trackers for CVE-2025-49794

vendor priority summary link
alpine CVE-2025-49794: 1 source package rows (libxml2); 4 state rows across 4 repos (3.21-main, 3.22-main, 3.23-main, edge-main); fixed 4, open 0. https://security.alpinelinux.org/vuln/CVE-2025-49794
debian not yet assigned CVE-2025-49794 not yet assigned priority: Debian including 1 source packages (libxml2), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2025-49794
redhat high https://access.redhat.com/security/cve/CVE-2025-49794
suse high CVE-2025-49794 severity important: SUSE including 350 source package names (0.23.1-11.20:libxml2-2-2.10.3-150500.5.29.1, 0.3.2-1.2:libxml2-2-2.10.3-150500.5.29.1, …), 1031 product×package rows across 374 product lines (Container bci/kiwi, Container bci/spack, … (374 product lines)): Fixed 769, Known Affected 221, Known Not Affected 41. https://www.suse.com/security/cve/CVE-2025-49794/
ubuntu medium CVE-2025-49794 medium priority: Ubuntu including 1 source packages (libxml2), 9 status rows across 9 suites (bionic, focal, jammy, noble, oracular, plucky, trusty, upstream, xenial): released 8, ignored 1. https://ubuntu.com/security/CVE-2025-49794

Affected software / configurations for CVE-2025-49794

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2025-49794

URL Tags
https://access.redhat.com/errata/RHSA-2025:10630
https://access.redhat.com/errata/RHSA-2025:10698
https://access.redhat.com/errata/RHSA-2025:10699
https://access.redhat.com/errata/RHSA-2025:11580
https://access.redhat.com/errata/RHSA-2025:12098
https://access.redhat.com/errata/RHSA-2025:12099
https://access.redhat.com/errata/RHSA-2025:12199
https://access.redhat.com/errata/RHSA-2025:12237
https://access.redhat.com/errata/RHSA-2025:12239
https://access.redhat.com/errata/RHSA-2025:12240
https://access.redhat.com/errata/RHSA-2025:12241
https://access.redhat.com/errata/RHSA-2025:13335
https://access.redhat.com/errata/RHSA-2025:15397
https://access.redhat.com/errata/RHSA-2025:15827
https://access.redhat.com/errata/RHSA-2025:15828
https://access.redhat.com/errata/RHSA-2025:18217
https://access.redhat.com/errata/RHSA-2025:18218
https://access.redhat.com/errata/RHSA-2025:18219
https://access.redhat.com/errata/RHSA-2025:18240
https://access.redhat.com/errata/RHSA-2025:19020
https://access.redhat.com/errata/RHSA-2025:19041
https://access.redhat.com/errata/RHSA-2025:19046
https://access.redhat.com/errata/RHSA-2025:19894
https://access.redhat.com/errata/RHSA-2025:21913
https://access.redhat.com/errata/RHSA-2026:0934
https://access.redhat.com/errata/RHSA-2026:7519
https://access.redhat.com/security/cve/CVE-2025-49794
https://bugzilla.redhat.com/show_bug.cgi?id=2372373
https://gitlab.gnome.org/GNOME/libxml2/-/issues/931
https://lists.debian.org/debian-lts-announce/2025/07/msg00014.html
https://cert-portal.siemens.com/productcert/html/ssa-253495.html
https://cert-portal.siemens.com/productcert/html/ssa-577017.html
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