# CVE-2026-79522: GPAC out-of-bounds read in downloader HTTP client

Source: https://junglewise.ai/threats/cve-2026-79522-gpac-out-of-bounds-read-in-downloader-http-client  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-09. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-79522 · Severity: medium · CVSS 6.5 · Published 2026-09-09

GPAC is a multimedia framework that handles streaming and media playback, including HTTP-based content delivery. An out-of-bounds memory read vulnerability in its HTTP downloader allows a remote attacker to crash GPAC by serving a specially crafted HTTP response with an oversized chunk size. This could disrupt media playback for users accessing content from a malicious server or during network-based attacks.

Technologies: [Gpac](https://junglewise.ai/threats/technologies/gpac). Vendors: [Gpac](https://junglewise.ai/threats/vendors/gpac).

## Quick answers

**Is CVE-2026-79522 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-79522 being exploited in the wild.

**How severe is CVE-2026-79522?** Medium severity, with a CVSS score of 6.5, published 9 September 2026.

**Which products and versions are affected?** Gpac v26.07.0.

**Is there a fix for CVE-2026-79522?** A patch was published on 2026-09-09: Fix committed in 2fd5a06ab226767900fd86edb5a1e8bfc1010640 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-79522 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-79522?** Check whether you run Gpac at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is an out-of-bounds read in the gf_dm_get_chunk_data and gf_dm_data_received functions (src/utils/downloader.c) that parse HTTP Transfer-Encoding: chunked responses. When a chunk size field of 0xFFFFFFFF (4GB-1) is received, it is accepted without upper-bound validation. A subsequent bounds check is bypassed via unsigned 32-bit integer wraparound (hdr_size + nbBytes wraps to a small value), causing a memcpy call to attempt reading 0xFFFFFFFF bytes from a ~4KB heap buffer. The attack requires network reachability to an HTTP server controlled by the attacker or a MITM position. Exploitation results in a deterministic process crash (SIGSEGV) due to reading far beyond allocated memory. A fix was committed in GPAC (commit 2fd5a06ab226767900fd86edb5a1e8bfc1010640).

## Affected products

- GPAC GPAC v26.07.0

## Timeline

- 2026-08-19: disclosed: Vulnerability reported on GitHub issue #3861
- 2026-09-09: patched: Fix committed in 2fd5a06ab226767900fd86edb5a1e8bfc1010640
- 2026-09-09: advisory: CVE-2026-79522 published

## References

- [https://github.com/gpac/gpac/commit/2fd5a06ab226767900fd86edb5a1e8bfc1010640](https://github.com/gpac/gpac/commit/2fd5a06ab226767900fd86edb5a1e8bfc1010640)
- [https://github.com/gpac/gpac/issues/3861](https://github.com/gpac/gpac/issues/3861)

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