avoid negative sample offsets in animated AVIF decoding

F-FIREFOX-AVIF-MP4PARSE-OFFSET-001

Public snapshot: 26 Sep 2026. Status, releases and attribution belong to each source below; none is inferred from another record.

Recorded evidence

—score not recorded

mozilla/gecko-devReported fixmozilla/gecko-dev

avoid negative sample offsets in animated AVIF decoding

Fixed in: Firefox 150 (vendor tracker status)

fixed publicly

details

Finding IDs: F-FIREFOX-AVIF-MP4PARSE-OFFSET-001
Status: fixed publicly
Fixed in: Firefox 150 (vendor tracker status)
Note: the public bug is RESOLVED FIXED and status-firefox150 is fixed. Mozilla labels it S2 and sec-other; this record does not translate S2 into a HIGH security severity or assert a CVE. The original report was not independently rerun against release binaries.

F-FIREFOX-AVIF-MP4PARSE-OFFSET-001: Input / state handling. Offset narrowing fails to preserve the required nonnegative range; exploitability is not asserted. Reviewed 24 Sep 2026. Mechanism assessed by 1seal.

Mechanism source for F-FIREFOX-AVIF-MP4PARSE-OFFSET-001

Security area (1seal assessment): Memory safety. Narrowing a sample offset can produce a negative read offset in the AVIF decode stream. Reviewed 23 Sep 2026.

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