CVE-2026-102633

libexpat 2.7.2 through 2.8.5 Integer Overflow in expat_realloc

CVE-2026-102633 is fixed in 5 products on 1 platform, first by DEBIAN-CVE-2026-102633, released October 10, 2026. It is not reported as exploited. Patch Radar priority: High.

High

CVSS

8.2

Moderate

Exploitation

None reported

No vendor assessment

CISA KEV

Not listed

Not in the Known Exploited Vulnerabilities catalog

EPSS

0.0037

30th percentile

libexpat versions 2.7.2 through 2.8.5 contain an integer overflow vulnerability in expat_realloc() function on 32-bit platforms when computing allocation sizes. Attackers supplying malicious XML to applications parsing with vulnerable libexpat can cause heap buffer overflow, memory corruption, or denial of service.

Where it's fixed

Product	Fixed in	Fix	Released
Linux
expat · Debian 12.15 (bookworm)	2.5.0-1+deb12u5	DEBIAN-CVE-2026-102633	Oct 10, 2026
expat · Debian 13.5 (trixie)	2.9.0-1~deb13u1	DEBIAN-CVE-2026-102633	Oct 10, 2026
expat · Debian 14	2.8.5-2	DEBIAN-CVE-2026-102633	Oct 10, 2026
expat · RHEL 10	2.7.3-1.el10_2.7	RHSA-2026:88248	Oct 24, 2026
expat · RHEL 8	0:2.5.0-6.el8_10	RHSA-2026:92323	Oct 30, 2026
expat · RHEL 9	0:2.5.0-6.el9_8.7	RHSA-2026:88247	Oct 24, 2026
expat · almalinux 10	2.7.3-1.el10_2.7	ALSA-2026:88248	Nov 7, 2026
expat · almalinux 8	2.5.0-6.el8_10	ALSA-2026:92323	Nov 7, 2026
expat · almalinux 9	2.5.0-6.el9_8.7	ALSA-2026:88247	Nov 7, 2026
expat · ol 10	0:2.7.3-1.el10_2.7	ELSA-2026-88248	Nov 7, 2026
expat · ol 8	0:2.5.0-6.el8_10	ELSA-2026-92323	Nov 7, 2026
expat · ol 9	0:2.5.0-6.el9_8.7	ELSA-2026-88247	Nov 7, 2026
expat · opensuse-leap 16.0	2.8.5-160000.1.1	OPENSUSE-SU-2026:22177-1	Nov 7, 2026
expat · rocky 10	0:2.7.3-1.el10_2.7	RLSA-2026:88248	Nov 7, 2026
expat · rocky 8	0:2.5.0-6.el8_10	RLSA-2026:92323	Nov 7, 2026
expat · rocky 9	0:2.5.0-6.el9_8.7	RLSA-2026:88247	Nov 7, 2026
expat · sles 15.6	2.8.5-150400.3.40.1	SUSE-SU-2026:4623-1	Nov 7, 2026
expat · sles 15.7	2.8.5-150700.3.15.1	SUSE-SU-2026:4619-1	Nov 7, 2026
expat · sles 16.0	2.8.5-160000.1.1	SUSE-SU-2026:24469-1	Nov 7, 2026
expat-devel · RHEL 8	0:2.5.0-6.el8_10	RHSA-2026:92323	Oct 30, 2026
expat-devel · RHEL 9	0:2.5.0-6.el9_8.7	RHSA-2026:88247	Oct 24, 2026
expat-devel · almalinux 8	2.5.0-6.el8_10	ALSA-2026:92323	Nov 7, 2026
expat-devel · almalinux 9	2.5.0-6.el9_8.7	ALSA-2026:88247	Nov 7, 2026
expat-devel · ol 10	0:2.7.3-1.el10_2.7	ELSA-2026-88248	Nov 7, 2026
expat-devel · ol 8	0:2.5.0-6.el8_10	ELSA-2026-92323	Nov 7, 2026
expat-devel · ol 9	0:2.5.0-6.el9_8.7	ELSA-2026-88247	Nov 7, 2026
firefox · amzn 2023	140.17.0-1.amzn2023.0.1	ALAS2023-2026-3214	Nov 7, 2026
firefox-debuginfo · amzn 2023	140.17.0-1.amzn2023.0.1	ALAS2023-2026-3214	Nov 7, 2026
firefox-debugsource · amzn 2023	140.17.0-1.amzn2023.0.1	ALAS2023-2026-3214	Nov 7, 2026

Details

Published
September 29, 2026
Weakness
Integer Overflow or Wraparound
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:L
Vendor advisory
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-102633

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