# CVE-2026-124309: Fraunhofer HHI VVdeC before 3.2.1 Heap Out-of-Bounds Read via SEIReader::xParseSEIScalableNesting

Status: published. Published: 2026-11-07. Updated: 2026-11-07.

Fraunhofer HHI VVdeC before 3.2.1 contains a heap out-of-bounds read vulnerability in SEIReader::xParseSEIScalableNesting that allows attackers to read past heap allocations by casting the SEI wrapper object instead of its payload. Attackers can supply a crafted VVC bitstream with a scalable nesting SEI containing a nested buffering period SEI to crash the decoder or copy adjacent heap memory.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://github.com/fraunhoferhhi/vvdec/commit/1d657c7a822987d2ff935e9c227c5faf5318ca06

## Affected products and versions

- fraunhoferhhi / vvdec (fraunhoferhhi/vvdec): ≥ 0; < 3.2.1 (affected, semver); 3.2.1 (unaffected, semver). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 6.9 (medium); CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 6.1 (medium); CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H; source: CNA: VulnCheck

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-125

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/fraunhoferhhi/vvdec/issues/397 (CNA: VulnCheck; issue-tracking)

- https://github.com/fraunhoferhhi/vvdec/commit/1d657c7a822987d2ff935e9c227c5faf5318ca06 (CNA: VulnCheck; patch)

- https://github.com/fraunhoferhhi/vvdec/blob/v3.2.0/source/Lib/DecoderLib/SEIread.cpp#L586-L592 (CNA: VulnCheck; technical-description)

- https://github.com/fraunhoferhhi/vvdec/blob/v3.2.0/source/Lib/CommonLib/Slice.h#L644 (CNA: VulnCheck; technical-description)

- https://github.com/fraunhoferhhi/vvdec (CNA: VulnCheck; product)

- https://www.vulncheck.com/advisories/fraunhofer-hhi-vvdec-before-3.2.1-heap-out-of-bounds-read-via-seireader-xparseseiscalablenesting (CNA: VulnCheck; third-party-advisory)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-124309; retrieved 2026-11-07; source updated 2026-11-07

Revision: 4c46617c0120468cb2aa302c399f81154f34b449259b1fb7684d4b5a8216b275

Canonical: https://y2.dev/cve/CVE-2026-124309

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