CVE-2026-117610
libexpat through 2.9.0 NULL Pointer Dereference via External Entity Subparser
- State
- Published
- Severity
- 8.2 High
- Published
- Oct 28, 2026
- Updated
- Oct 28, 2026
- Reserved
- Oct 27, 2026
Description
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 empty non-final first parse on an external entity subparser, causing a later parse to crash the application.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 8.2 High | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N | VulnCheck |
| 3.1 | 5.9 Medium | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H | VulnCheck |
Weaknesses
- CWE-476 NULL Pointer Dereference
Affected Products
| Product | Versions |
|---|---|
libexpatlibexpat |
|
References
- https://github.com/libexpat/libexpat/pull/1444patchissue-tracking
- https://github.com/libexpat/libexpat/commit/7b0d50e4b1d16fafd55876260701e04279a7489dpatch
- https://github.com/libexpat/libexpat/blob/a76b1174c1ea52abb639a4c69d52b630a8a106a2/expat/lib/xmlparse.c#L3468-L3510technical-description
- https://github.com/libexpat/libexpatproduct
- VulnCheck Advisory: libexpat through 2.9.0 NULL Pointer Dereference via External Entity Subparserthird-party-advisory
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