CVE-2024-45491

An issue was discovered in libexpat before 2.6.3. dtdCopy in xmlparse.c can have an integer overflow for nDefaultAtts on 32-bit platforms (where UINT_MAX equals SIZE_MAX).

Published: 2024-08-30 Last update: 2026-05-12 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2024-45491 is rated High Risk (66.7/100): CVSS Critical severity, with medium exploitation likelihood (EPSS 1.14%). High exploitation likelihood—assess exposure and prioritize 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-2024-45491

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 2026-06-02 1.17% 1.14% -0.03%
2 2026-05-28 1.44% 1.17% -0.26%
3 2026-05-22 — 1.44% —

Full EPSS history (25 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2024-45491

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.8 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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: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.
 3.9 5.9 [email protected]
7.3 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L 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:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 3.9 3.4 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2024-45491

GitHub Security Advisory for CVE-2024-45491

GHSA-784x-7qm2-gp97 · Severity: high — An issue was discovered in libexpat before 2.6.3. dtdCopy in xmlparse.c can have an integer...

OS Trackers for CVE-2024-45491

vendor priority summary link
alpine — CVE-2024-45491: 3 source package rows (expat, qt5-qtwebengine, qt6-qtwebengine); 19 state rows across 11 repos (3.17-main, 3.18-main, 3.19-main, 3.20-community, 3.20-main, 3.21-community, 3.21-main, 3.22-community, 3.22-main, edge-community, edge-main); fixed 14, open 5. https://security.alpinelinux.org/vuln/CVE-2024-45491
debian not yet assigned CVE-2024-45491 not yet assigned priority: Debian including 2 source packages (expat, libxmltok), 7 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5, open 2. https://security-tracker.debian.org/tracker/CVE-2024-45491
gentoo high CVE-2024-45491: 1 GLSA(s) (202501-09), 1 atom(s) (dev-qt/qtwebengine); latest impact high. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2024-45491
redhat medium — https://access.redhat.com/security/cve/CVE-2024-45491
suse medium CVE-2024-45491 severity moderate: SUSE including 380 source package names (0.0.17-1.1:libexpat1-2.4.4-150400.3.22.1, 0.1.6-1.2:libexpat1-2.4.4-150400.3.22.1, …), 866 product×package rows across 345 product lines (Container bci/bci-init, Container bci/bci-sle15-kernel-module-devel, … (345 product lines)): Fixed 644, Known Affected 216, Known Not Affected 6. https://www.suse.com/security/cve/CVE-2024-45491/
ubuntu medium CVE-2024-45491 medium priority: Ubuntu including 23 source packages (apache2, apr-util, …), 208 status rows across 10 suites (bionic, focal, jammy, noble, oracular, plucky, questing, trusty, upstream, xenial): needs-triage 71, not-affected 68, DNE 37, ignored 18, released 13, needed 1. https://ubuntu.com/security/CVE-2024-45491

Affected software / configurations for CVE-2024-45491

Vendor Product Version Raw CPE
libexpat_project libexpat < 2.6.3 cpe:2.3:a:libexpat_project:libexpat:*:*:*:*:*:*:*:*

References for CVE-2024-45491

cvelogic Threat Intelligence