Soumettre #846851: GPAC commit a95e79308 - b40ce70f5 Heap-based Buffer Overflow

A heap-based out-of-bounds read vulnerability exists in GPAC MP4Box in the ISOBMFF sample group description cleanup logic. The issue
affects sgpd_del_entry() in src/isomedia/box_code_base.c when MP4Box processes crafted AV1 input through the -cat operation.

AV1 switching frame sample groups use the GF_ISOM_SAMPLE_GROUP_AV1S grouping type. Their entries are created by sg_av1s_create_entry() in
src/isomedia/isom_write.c as GF_AV1SwitchingEntry objects, which only contain a 4-byte dummy field. However, sgpd_del_entry() does not
contain a dedicated case for GF_ISOM_SAMPLE_GROUP_AV1S. As a result, AV1S entries fall through to the default deletion logic and are
incorrectly cast to GF_DefaultSampleGroupDescriptionEntry.

The default entry type contains a data pointer at offset 8. When sgpd_del_entry() checks ptr->data, it reads 8 bytes from outside the 4-
byte GF_AV1SwitchingEntry allocation, causing a heap-buffer-overflow. This occurs during cleanup after an import failure, when
sgpd_box_del() destroys the sample group description box.

The vulnerability can be triggered with a crafted AV1 media file using:

./MP4Box -cat <crafted_file> white.mp4 -out /dev/null

Successful exploitation can cause MP4Box to crash, resulting in denial of service. The root cause is a missing GF_ISOM_SAMPLE_GROUP_AV1S
deletion branch in sgpd_del_entry(), causing a type confusion between AV1S sample group entries and default sample group description
entries.

• La source: ⚠️ https://github.com/gpac/gpac/issues/3398
• Utilisateur: noki (UID 98507)
• Soumission: 03/06/2026 14:32 (il y a 1 mois)
• Modérer: 04/07/2026 07:16 (1 month later)
• Statut: Accepté
• Entrée VulDB: 376293 [GPAC jusqu’à b40ce70f5 MP4Box box_code_base.c sgpd_del_entry data buffer overflow]
• Points: 20