Use-after-free when XML includes have duplicated entities

Librsvg uses libxml2, a C library, to parse XML. When librsvg parses an SVG document which has a nested Xinclude, an XML entity declaration with a duplicate name as an existing one can cause a use-after-free error. While libxml2 is expanding an internal entity, a recursive XInclude can parse another document that declares an entity with the same name. Both parses use the same `XmlState` entity map on the librsvg side. `entity_insert()` replaces the first entry, whose `Drop` implementation calls `xmlFreeNode()`. The outer `xmlCtxtParseEntity()` then keeps using the freed 144-byte `xmlEntity`. The included parse should not free an entity that the outer parser is still using. The fix is in commit 8a1b0cd319e9af2d1e9cf878081dd77f227a0504, where librsvg will no longer free xmlEntity pointers that libxml2 is still using.

Source published

23 Sep 2026 12:00:00 UTC

Source modified

23 Oct 2026 06:45:38 UTC

Observed here

24 Oct 2026 13:19:54 UTC

Source terms

OSV · upstream source license applies

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