# CVE-2026-71612: GPAC buffer overflow in nhntdmx_process via long file path

Source: https://junglewise.ai/threats/cve-2026-71612-gpac-buffer-overflow-in-nhntdmx-process-via-long-file-path  
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-2026-71612 · Severity: high · CVSS 8.4 · Published 2026-09-09

GPAC is an open-source multimedia framework used to process audio and video files. A stack buffer overflow in the NHNT (Networked Hint Track) file handler allows an attacker to crash the application or execute arbitrary code by providing a file with an excessively long path exceeding 1000 bytes. Exploitation requires only the ability to place a file at a crafted path or convince a user to open one.

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

## Quick answers

**Is CVE-2026-71612 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-71612 being exploited in the wild.

**How severe is CVE-2026-71612?** High severity, with a CVSS score of 8.4, published 9 September 2026.

**Which products and versions are affected?** Gpac prior to fac50e6a12ac27ffabdd5d3080b51afcc44ad8d6 (commit c2dee3aff638cd96f9617ac5b17dc2868cd90ef3 and earlier).

**Is there a fix for CVE-2026-71612?** A patch was published on 2026-09-09: Fix released in commit fac50e6a12ac27ffabdd5d3080b51afcc44ad8d6 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-71612 attacked?** It is attacked with local access, in a software library.

**Am I affected by CVE-2026-71612?** 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 a stack buffer overflow in the nhntdmx_process() function in dmx_nhnt.c. The root cause is a logic flaw in path validation: a 1000-byte stack buffer (szMedia) is initially filled safely using strncpy, but later the code uses an unsafe strcpy to re-copy the original untruncated file path into the buffer at line 379. The length check at line 323 operates on a strrchr-truncated version of the path (after extension removal), not the original path, rendering it ineffective. An attacker crafting a path longer than 1000 bytes with an early dot character (e.g., "a.bbb/d1/d2/...") bypasses validation and triggers overflow. The attack surface includes any use of GPAC's NHNT processing: the command-line tool, MP4Box, or applications using libgpac. The vulnerability was fixed in commit fac50e6a12ac27ffabdd5d3080b51afcc44ad8d6 by replacing the unsafe strcpy with gf_strlcpy.

## Affected products

- GPAC GPAC prior to fac50e6a12ac27ffabdd5d3080b51afcc44ad8d6 (commit c2dee3aff638cd96f9617ac5b17dc2868cd90ef3 and earlier)

## Timeline

- 2026-06-09: disclosed: Issue #3612 opened on GitHub
- 2026-09-09: patched: Fix released in commit fac50e6a12ac27ffabdd5d3080b51afcc44ad8d6
- 2026-09-09: advisory: CVE-2026-71612 published

## References

- [https://github.com/gpac/gpac/commit/fac50e6a12ac27ffabdd5d3080b51afcc44ad8d6](https://github.com/gpac/gpac/commit/fac50e6a12ac27ffabdd5d3080b51afcc44ad8d6)
- [https://github.com/gpac/gpac/issues/3612](https://github.com/gpac/gpac/issues/3612)

## Related threats

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- [GPAC use after free in MP4Box filter queue](https://junglewise.ai/threats/cve-2026-108539-a-vulnerability-was-detected-in-gpac-up-to-26-07-0-this-affects)
- [GPAC buffer overflow in DASH Client URL resolution](https://junglewise.ai/threats/cve-2026-103227-a-weakness-has-been-identified-in-gpac-up-to-26-07-0-affected-by)