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.
Weakness
The product dereferences a pointer that it expects to be valid but is NULL.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Matanza | Ubuntu | devel | * |
| Matanza | Ubuntu | esm-apps/focal | * |
| Matanza | Ubuntu | esm-apps/jammy | * |
| Matanza | Ubuntu | esm-apps/noble | * |
| Matanza | Ubuntu | esm-apps/resolute | * |
| Matanza | Ubuntu | jammy | * |
| Matanza | Ubuntu | noble | * |
| Matanza | Ubuntu | resolute | * |
| Matanza | Ubuntu | stonking | * |
Potential Mitigations
References
- https://github.com/libexpat/libexpat
- https://github.com/libexpat/libexpat/blob/a76b1174c1ea52abb639a4c69d52b630a8a106a2/expat/lib/xmlparse.c#L3468-L3510
- https://github.com/libexpat/libexpat/commit/7b0d50e4b1d16fafd55876260701e04279a7489d
- https://github.com/libexpat/libexpat/pull/1444
- https://www.vulncheck.com/advisories/libexpat-through-2.9.0-null-pointer-dereference-via-external-entity-subparser