# CVE-2026-125178: FFmpeg through 9.0.2 Out-of-Bounds Heap Read via TDSC Cursor Dimensions

Status: published. Published: 2026-11-09. Updated: 2026-11-13.

FFmpeg through 9.0.2 contains an out-of-bounds heap read vulnerability in tdsc_load_cursor() in libavcodec/tdsc.c, which stores cursor dimensions before validating them. Attackers can supply a crafted AVI file with oversized TDSC cursor dimensions so tdsc_paint_cursor() reads past the cursor buffer, crashing the decoder or leaking heap memory into frames.

## 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/FFmpeg/FFmpeg/commit/12c589a37d093cc55618f8377b092dc21416806f

## Affected products and versions

- FFmpeg / FFmpeg (ffmpeg/ffmpeg): ≥ 0; ≤ 9.0.2 (affected, 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

- 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X; source: NVD: disclosure@vulncheck.com

- 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: NVD: disclosure@vulncheck.com

- CISA KEV: No listing in collected sources

- EPSS: 0.13% as of 2026-11-12; percentile 2.59%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-125

## Exploit evidence

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

## References

- https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/24682 (CNA: VulnCheck; issue-tracking)

- https://github.com/FFmpeg/FFmpeg/commit/12c589a37d093cc55618f8377b092dc21416806f (CNA: VulnCheck; patch)

- https://github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/tdsc.c#L207 (CNA: VulnCheck; technical-description)

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

- https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-out-of-bounds-heap-read-via-tdsc-cursor-dimensions (CNA: VulnCheck; third-party-advisory)

- https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/24682 (disclosure@vulncheck.com)

- https://github.com/FFmpeg/FFmpeg (disclosure@vulncheck.com)

- https://github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/tdsc.c#L207 (disclosure@vulncheck.com)

- https://github.com/FFmpeg/FFmpeg/commit/12c589a37d093cc55618f8377b092dc21416806f (disclosure@vulncheck.com)

- https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-out-of-bounds-heap-read-via-tdsc-cursor-dimensions (disclosure@vulncheck.com)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-125178; retrieved 2026-11-13; source updated 2026-11-13

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-125178; retrieved 2026-11-11; source updated 2026-11-10

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-125178; retrieved 2026-11-13; source updated Not reported

Revision: 925fa37f5386626bdfbba714363da5fabb033140966f935431fd5ccab5fc4199

Canonical: https://y2.dev/cve/CVE-2026-125178

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