MinorCritical vulnerability

CVE-2026-125218 (CVSS 7.3)

NVD · officialPublished Nov 9, 2026Risk 23/100

FFmpeg through 9.0.2 contains a heap buffer overflow vulnerability in the APNG encoder's encode_apng() function in libavcodec/pngenc.c when frame size changes mid-stream. Attackers can supply crafted media whose resolution grows mid-stream, causing APNG_DISPOSE_OP_BACKGROUND memset writes past prev_frame and crashing or corrupting heap memory in transcoding applications.

Technical details

CVSS

7.3

AV:LocalAC:HighPR:NoneUI:Passive

Evidence and sources

This record is attributed to NVD. Exploitation status and remediation guidance are kept separate from the vulnerability's technical severity.

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