CVE-2026-118370
highlibexpat through 2.9.0 contains a signed integer overflow vulnerability in storeAtts() in lib/xmlparse.c that allows attackers to trigger out-of-bounds writes…
Vendor / product: Libexpat Project — libexpat
libexpat through 2.9.0 contains a signed integer overflow vulnerability in storeAtts() in lib/xmlparse.c that allows attackers to trigger out-of-bounds writes via oversized attribute counts. Attackers can supply a multi-gigabyte document with a start tag carrying over 2^30 attributes to overflow attIndex and nPrefixes, crashing applications or corrupting heap memory.
CVSS
8.2
8.2 (CVSS v3.1)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H Severity source: NVD CVSS v3.1 (nvd@nist.gov)
Timeline (UTC)
Published: 2026-10-28 03:17
Modified: 2026-11-02 20:17
NVD status: Analyzed
Last synced 1 day ago
Verified against the source API 2026-11-03 07:35 UTC
Exploitation
Not listed in CISA KEV (as of last catalog sync)
Absence from KEV does not mean a CVE is not exploited. Exploitation status: unknown (no authoritative evidence in our sources).
Affected products
libexpat_project / libexpat ≤2.9.0
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
Patch / mitigation: https://github.com/libexpat/libexpat/commit/1bac53c4fc460a03cd9860f39501c7979f6750ae
Patch / mitigation: https://github.com/libexpat/libexpat/commit/621cb2c78b253ee023a86bc91d6ddb048481c04c
Patch / mitigation: https://github.com/libexpat/libexpat/pull/1450
References
- https://github.com/libexpat/libexpat disclosure@vulncheck.com
- https://github.com/libexpat/libexpat/blob/a76b1174c1ea52abb639a4c69d52b630a8a106a2/expat/l... disclosure@vulncheck.com
- https://github.com/libexpat/libexpat/commit/1bac53c4fc460a03cd9860f39501c7979f6750ae disclosure@vulncheck.com
- https://github.com/libexpat/libexpat/commit/621cb2c78b253ee023a86bc91d6ddb048481c04c disclosure@vulncheck.com
- https://github.com/libexpat/libexpat/pull/1450 disclosure@vulncheck.com
- https://www.vulncheck.com/advisories/libexpat-through-2.9.0-integer-overflow-in-storeatts-... disclosure@vulncheck.com
Data sources
NVD CVE API 2.0 — fetched 2026-11-03 07:35 UTC · record ↗