# CVE-2026-124307: Fraunhofer HHI VVdeC before 3.2.1 Heap Use-After-Free via ALF APS Redefinition

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

Fraunhofer HHI VVdeC before 3.2.1 contains a heap use-after-free vulnerability that allows attackers to corrupt memory by redefining an ALF adaptation parameter set id still referenced by slices. Attackers can supply a crafted VVC bitstream that, with multithreaded decoding, makes worker threads dereference freed APS objects in CABACReader::readAlf() and AdaptiveLoopFilter::reconstructCoeff(), causing crashes or heap corruption.

## 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/1eddb30c4b8e02f3d13ba24aa7e52f1aa7b08c01

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

- CVSS 3.1: 5.8 (medium); CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:H; source: CNA: VulnCheck

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-416

## Exploit evidence

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

## References

- https://github.com/fraunhoferhhi/vvdec/issues/391 (CNA: VulnCheck; issue-tracking)

- https://github.com/fraunhoferhhi/vvdec/issues/390 (CNA: VulnCheck; issue-tracking)

- https://github.com/fraunhoferhhi/vvdec/commit/1eddb30c4b8e02f3d13ba24aa7e52f1aa7b08c01 (CNA: VulnCheck; patch)

- https://github.com/fraunhoferhhi/vvdec/blob/v3.2.0/source/Lib/CommonLib/Slice.h#L2570 (CNA: VulnCheck; technical-description)

- https://github.com/fraunhoferhhi/vvdec/blob/v3.2.0/source/Lib/CommonLib/ParameterSetManager.h#L97 (CNA: VulnCheck; technical-description)

- https://github.com/fraunhoferhhi/vvdec/blob/v3.2.0/source/Lib/DecoderLib/CABACReader.cpp#L428-L429 (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-use-after-free-via-alf-aps-redefinition (CNA: VulnCheck; third-party-advisory)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-124307; retrieved 2026-11-07; source updated 2026-11-07

Revision: 552c1b21c3e2e6129d798e971042921060d98477c63f7188289710baac94f72d

Canonical: https://y2.dev/cve/CVE-2026-124307

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