| Title | GPAC up to commit f1219cde (2026-07-25) Denial of Service |
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| Description | A vulnerability was found in GPAC up to commit f1219cde (2026-07-25) and classified as problematic. Affected is the scene graph node handling related to instance counting in the component MP4Box. The manipulation via a crafted MP4 file processed with the -nstatx argument leads to a reachable assertion failure (assert(num_instances)) that causes an immediate process abort. It is possible to launch the attack locally. User interaction is required.
Technical Details
- Affected file/function: scenegraph/base_scenegraph.c:753 / gf_node_unregister
- Vulnerable parameter: Malformed ISO data (corrupted stts, unknown/incomplete boxes) leading to corrupted node instance tracking
- Attack vector: Local
- Privileges required: None
- Trigger condition: Processing a crafted MP4 file with "MP4Box -nstatx" causes malformed ISO parsing that corrupts scene graph node state. A node's instance counter reaches zero, but is still accessed during scene analysis, triggering assert(pNode->sgprivate->num_instances) at base_scenegraph.c:753. Requires --enable-debug build.
Impact
- Confidentiality: None
- Integrity: None
- Availability: High
CVSS v3.1
Score: 5.5 (Medium)
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Timeline
- Discovered: 2026-07-27
- Vendor notified: 2026-07-27
- Patch released: 2026-07-28
- Public disclosure: 2026-07-27
Countermeasure
Apply the upstream patch. Replace the reachable assertion with proper error handling that checks node instance count before access. |
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| Source | ⚠️ https://github.com/r1ck9-2q/cve_summit/blob/main/Vuln%20GPAC%20MP4Box%20Assertion%20Failure%20assert(num_instances).md |
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| User | r1ck9 (UID 97869) |
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| Submission | 08/03/2026 07:19 (2 months ago) |
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| Moderation | 09/13/2026 06:55 (1 month later) |
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| Status | Accepted |
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| VulDB entry | 403216 [GPAC up to f1219cde MP4Box base_scenegraph.c gf_node_unregister assertion] |
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| Points | 20 |
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