CVE-2026-64830 | FFmpeg versions 2.1 through 8.1.2 contains a heap buffer ove… | CVSS 8.8 HIGH

Description

FFmpeg versions 2.1 through 8.1.2 contains a heap buffer overflow vulnerability in the VobSub subtitle demuxer that allows attackers to corrupt adjacent heap memory by supplying a malicious .sub/.idx subtitle file declaring more distinct stream IDs than the fixed-size array bounds in libavformat/mpeg.c. Attackers can craft a subtitle file with excessive distinct stream IDs to trigger unbounded writes beyond the vobsub->q[] array boundary via ff_subtitles_queue_insert(), potentially achieving arbitrary code execution in any application using FFmpeg's VobSub demuxer.

Metadata

CVE ID: CVE-2026-64830
State: PUBLISHED
Assigner: VulnCheck
Reserved: 2026-07-20 18:27 UTC
Published: 2026-07-22 16:33 UTC
Last updated: 2026-07-22 17:24 UTC
Primary CWE: CWE-122
Heap-based Buffer Overflow
Vendor / Product: FFmpeg / FFmpeg
Sources: cve.org · NVD

Severity & Metrics

8.8 HIGH CVSS 3.1

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

SSVC — CISA Coordinator

Exploitation: none
Automatable: no
Tech. Impact: total

Affected products (1)

Vendor	Product	Platform	Versions
FFmpeg	FFmpeg	—	2.1 ≤ 8.1.2, dbd495f066a85ba96b17433f4306582aa37c3951

Weakness (CWE)

CWE	Source	Description
CWE-122	cna	Heap-based Buffer Overflow

CVSS scores (2)

Score	Severity	Version	Source	Vector
8.8	HIGH	3.1	cna	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
8.7	HIGH	4.0	cna	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

References (3)