FFmpeg through 9.0.2 contains an information disclosure vulnerability in flashsv_decode_block() in libavcodec/flashsv.c that copies uninitialized heap memory into decoded frames when inflate output is short. Attackers can supply a crafted FLV with an FSV1 stream whose zlib block data decompresses short, then recover heap contents from the decoded or re-encoded output.

Attack Vector Local

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction Passive

Vulnerable System Confidentiality Impact Low

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Local

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact Low

Integrity Impact None

Availability Impact None

User Interaction Required

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
FFmpeg FFmpeg unaffected
Version Status Constraints
0 affected ≤ 9.0.2

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Project Subscriptions

Vendors Products
Ffmpeg Subscribe
Ffmpeg Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/24464 cve-icon cve-icon
https://github.com/FFmpeg/FFmpeg cve-icon cve-icon
https://github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/flashsv.c#L248 cve-icon cve-icon
https://github.com/FFmpeg/FFmpeg/commit/50d206a75b5e60261d71b25657ae04891eb60290 cve-icon cve-icon
https://github.com/FFmpeg/FFmpeg/commit/cfb40c912927fdd2c1186b7b6aca468422da23db cve-icon cve-icon
https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-information-disclosure-via-flash-screen-video-decoder cve-icon cve-icon
History

Mon, 09 Nov 2026 19:15:00 +0000

Type Values Removed Values Added
Description FFmpeg through 9.0.2 contains an information disclosure vulnerability in flashsv_decode_block() in libavcodec/flashsv.c that copies uninitialized heap memory into decoded frames when inflate output is short. Attackers can supply a crafted FLV with an FSV1 stream whose zlib block data decompresses short, then recover heap contents from the decoded or re-encoded output.
Title FFmpeg through 9.0.2 Information Disclosure via Flash Screen Video Decoder
First Time appeared Ffmpeg
Ffmpeg ffmpeg
Weaknesses CWE-908
CPEs cpe:2.3:a:ffmpeg:ffmpeg:*:*:*:*:*:*:*:*
Vendors & Products Ffmpeg
Ffmpeg ffmpeg
References
Metrics cvssV3_1

{'score': 3.3, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N'}

cvssV4_0

{'score': 4.8, 'vector': 'CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-11-09T19:11:02.883Z

Reserved: 2026-11-09T18:15:03.846Z

Link: CVE-2026-125175

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-11-09T19:16:52.527

Modified: 2026-11-09T19:16:52.527

Link: CVE-2026-125175

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses