CVE-2026-125209: FFmpeg before 8.1.3 and 9.x before 9.0.2 Heap Buffer Overflow via dvdsubenc.c

Q: What conditions are required to trigger the overflow?

An attacker must provide crafted bitmap subtitle content with odd-width rectangles and cause it to be transcoded using FFmpeg's dvdsub encoder. The attack vector is local and user interaction is required.

Q: Which releases should be considered affected?

FFmpeg releases before 8.1.3 are affected, as are 9.x releases before 9.0.2. The provided data does not identify other affected release lines.

Q: What is the impact if exploitation succeeds?

The crafted subtitle data can cause a write past the encoder's output buffer, corrupting heap memory. The severity vector rates confidentiality, integrity, and availability impact as high.

Published Nov 9, 2026

Updated

FFmpeg before 8.1.3 and 9.x before 9.0.2 contains a heap buffer overflow vulnerability in the DVD subtitle encoder that underestimates RLE output size for odd-width rectangles. Attackers can supply files with crafted bitmap subtitles that, when transcoded to the dvdsub encoder, write past the output buffer and corrupt heap memory.

Affected Software

1 affected component

FFmpeg FFmpeg<8.1.3, >=9.0.0<9.0.2

Event History

Nov 9, 2026

CVE Published

via MITRE·07:11 PM

Data Sourced

via MITRE·07:11 PM

DescriptionSeverityWeakness

Data Sourced

via NVD·07:16 PM

DescriptionSeverityWeakness

Frequently Asked Questions

What conditions are required to trigger the overflow?

An attacker must provide crafted bitmap subtitle content with odd-width rectangles and cause it to be transcoded using FFmpeg's dvdsub encoder. The attack vector is local and user interaction is required.

Which releases should be considered affected?

FFmpeg releases before 8.1.3 are affected, as are 9.x releases before 9.0.2. The provided data does not identify other affected release lines.

What is the impact if exploitation succeeds?

The crafted subtitle data can cause a write past the encoder's output buffer, corrupting heap memory. The severity vector rates confidentiality, integrity, and availability impact as high.

CVE-2026-125209: FFmpeg before 8.1.3 and 9.x before 9.0.2 Heap Buffer Overflow via dvdsubenc.c

Affected Software

Event History

Frequently Asked Questions

What conditions are required to trigger the overflow?

Which releases should be considered affected?

What is the impact if exploitation succeeds?

Company

Resources

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Frequently Asked Questions

What conditions are required to trigger the overflow?

Which releases should be considered affected?

What is the impact if exploitation succeeds?