# CVE-2026-124309: Fraunhofer HHI VVdeC heap out-of-bounds read in SEI parsing

Source: https://junglewise.ai/threats/cve-2026-124309-fraunhofer-hhi-vvdec-before-3-2-1-contains-a-heap-out-of-bounds  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-07. Updated: 2026-11-07  
License: CC BY 4.0 with a link back

CVE-2026-124309 · Severity: medium · CVSS 6.1 · Published 2026-11-07

Fraunhofer HHI VVdeC is a VVC video decoder used in video processing applications. A heap out-of-bounds read vulnerability in the SEI (Supplemental Enhancement Information) parser allows attackers to crash the decoder or leak adjacent memory by supplying a malformed VVC video bitstream.

Technologies: [Fraunhofer HHI VVdeC](https://junglewise.ai/threats/technologies/vvdec). Vendors: [Fraunhofer HHI](https://junglewise.ai/threats/vendors/fraunhofer-hhi).

## Quick answers

**Is CVE-2026-124309 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-124309 being exploited in the wild.

**How severe is CVE-2026-124309?** Medium severity, with a CVSS score of 6.1, published 7 November 2026.

**Which products and versions are affected?** Fraunhofer HHI VVdeC before 3.2.1.

**Is there a fix for CVE-2026-124309?** Yes: fixed in 3.2.1. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-124309 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-124309?** Check whether you run Fraunhofer HHI VVdeC 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.

## How to fix

- Fixed in 3.2.1

## Technical details

The vulnerability exists in SEIReader::xParseSEIScalableNesting, where the code incorrectly casts a SEI wrapper object instead of its payload, leading to out-of-bounds heap reads. An attacker can craft a VVC bitstream with a scalable nesting SEI containing a nested buffering period SEI to trigger memory corruption. The flaw affects versions before 3.2.1.

## Affected products

- Fraunhofer HHI VVdeC before 3.2.1

## Timeline

- 2026-11-07: disclosed

## References

- [https://github.com/fraunhoferhhi/vvdec](https://github.com/fraunhoferhhi/vvdec)
- [https://github.com/fraunhoferhhi/vvdec/blob/v3.2.0/source/Lib/CommonLib/Slice.h](https://github.com/fraunhoferhhi/vvdec/blob/v3.2.0/source/Lib/CommonLib/Slice.h)

## Related threats

- [Fraunhofer HHI VVdeC heap out-of-bounds read](https://junglewise.ai/threats/cve-2026-124312-fraunhofer-hhi-vvdec-through-3-2-1-contains-a-heap-out-of-bounds)
- [Fraunhofer HHI VVdeC NULL pointer dereference in InterPrediction](https://junglewise.ai/threats/cve-2026-124311-fraunhofer-hhi-vvdec-through-3-2-1-contains-a-null-pointer)
- [Fraunhofer HHI VVdeC out-of-bounds read in inter prediction](https://junglewise.ai/threats/cve-2026-124310-fraunhofer-hhi-vvdec-before-3-2-1-contains-an-out-of-bounds-read)
- [Fraunhofer HHI VVdeC heap use-after-free in createSubPicRefBufs](https://junglewise.ai/threats/cve-2026-124308-fraunhofer-hhi-vvdec-before-3-2-1-contains-a-heap-use-after-free)
- [Fraunhofer HHI VVdeC heap use-after-free in ALF decoding](https://junglewise.ai/threats/cve-2026-124307-fraunhofer-hhi-vvdec-before-3-2-1-contains-a-heap-use-after-free)