libexpat has 7 CVEs on record. Disclosure cadence is accelerating: 7 in the last 90 days against 0 in the 90 before. The busiest recent month was October 2026 with 5. The median CVSS is 5.9 (medium). None have a confirmed exploitation report.
CVEs per month
Last 12 months, by publish date
- Exploited share
- 0% vs 1% corpus
- Median CVSS
- 5.9
- Publish → KEV
- —
- Last 90 days
- 7 prev 0
Worst active — by depth score
CVE-2026-115506High· 7.5libexpat through 2.9.0 Denial of Service via Billion Laughs Detection Delay53CVE-2026-77214High· 8.2libexpat before commit 13c5f63 contains a heap buffer over-read vulnerability in xmlparse.c45CVE-2026-93990High· 7.5Expat before 2.8.5 fails to validate that a high surrogate in UTF-16 input is followed by a low surrogate, allowing malformed UTF-16 sequences to be accepted41CVE-2026-113351Medium· 5.9libexpat 2.7.2 through 2.9.0 Denial of Service via XML_ParserReset33CVE-2026-102633Medium· 5.9libexpat versions 2.7.2 through 2.8.5 contain an integer overflow vulnerability in expat_realloc() function on 32-bit platforms when computing allocation sizes33
libexpat vulnerabilities
CVEs affecting libexpat, newest first. Open any entry for full detail, references, and exploit status.
7 CVEsRSS
CVE-2026-118370Medium· 5.9libexpat through 2.9.0 Integer Overflow in storeAtts via attIndex and nPrefixes
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…
CVE-2026-117610Medium· 5.9libexpat through 2.9.0 NULL Pointer Dereference via External Entity Subparser
libexpat through 2.9.0 contains a NULL pointer dereference vulnerability in externalEntityInitProcessor2() in lib/xmlparse.c that mishandles the XML_TOK_NONE token from empty input. Attackers who control stream chunking can force an empt…
CVE-2026-115506High· 7.5PoClibexpat through 2.9.0 Denial of Service via Billion Laughs Detection Delay
libexpat through 2.9.0 contains a denial of service vulnerability because billion laughs protection in accountingDiffTolerated() in xmlparse.c detects entity amplification too late. Attackers can supply a moderately sized XML document wi…
CVE-2026-113351Medium· 5.9libexpat 2.7.2 through 2.9.0 Denial of Service via XML_ParserReset
libexpat 2.7.2 through 2.9.0 contains a denial of service vulnerability because XML_ParserReset zeroes the direct byte count but never offsets tracked heap allocations. Attackers can submit a large XML document so later documents on the …
CVE-2026-77214High· 8.2libexpat before commit 13c5f63 contains a heap buffer over-read vulnerability in xmlparse.c
libexpat before commit 13c5f63 contains a heap buffer over-read vulnerability in xmlparse.c. XML_ParseBuffer advances the parse buffer end with parser->m_bufferEnd += len using a caller-supplied length that is not validated against the a…
CVE-2026-102633Medium· 5.9libexpat 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
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 li…
CVE-2026-93990High· 7.5Expat before 2.8.5 fails to validate that a high surrogate in UTF-16 input is followed by a low surrogate, allowing malformed UTF-16 sequences to be accepted
Expat before 2.8.5 fails to validate that a high surrogate in UTF-16 input is followed by a low surrogate, allowing malformed UTF-16 sequences to be accepted. Attackers can supply UTF-16 encoded XML containing lone high surrogates that c…