CVE-2026-70631: ffmpeg Use of Uninitialized Resource
Vulnerability summary
CVE-2026-70631 is a medium (CVSS 6.8) Use of Uninitialized Resource vulnerability in ffmpeg. EPSS estimates a 0.18% chance of exploitation in the next 30 days, higher than 6.8% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 9 · Related 8Timeline
- 06-08-2026PublishedVulnerability first disclosed.
- 14-08-2026Last modifiedVulnerability information updated.
Description
FFmpeg versions from 0.5 up to, but not including, 9.0 contain an uninitialized heap memory disclosure vulnerability in the native TIFF decoder in libavcodec/tiff.c. An attacker who can cause FFmpeg to decode a crafted TIFF file can supply a valid Deflate-compressed strip that terminates successfully after producing fewer bytes than the declared strip requires. The tiff_unpack_zlib() function allocates a heap buffer sized for the full declared strip but copies all declared rows via memcpy() regardless of how many bytes zlib actually decompressed, causing unwritten bytes that can contain stale data from prior heap allocations to be incorporated into decoded image output and potentially exposing sensitive data in persistent services.
CVSS metrics
9 scores · 6 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated6.8MediumCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
- OSV · DebianEcosystem advisory · calculated6.8MediumCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- OSV · WolfiEcosystem advisory · calculated6.8MediumCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
- OSV · ChainguardEcosystem advisory · calculated6.8MediumCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
- NVDNIST6.8MediumCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- OSV · UbuntuEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
- NVDNIST5.5MediumCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
EPSS trend
Probability
0.18%
Chance of exploitation in the next 30 days
Percentile
7%
Versus all other CVEs
30-day change
+0.05 pp
From 0.13% on 18-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Chainguard18 products
- eco-python-ffmpeg-6-minimalAll versions (No fix recorded)
- eco-python-ffmpeg-6-minimal-devAll versions (No fix recorded)
- eco-python-ffmpeg-6-minimal-staticAll versions (No fix recorded)
- eco-python-ffmpeg-7-minimalAll versions (No fix recorded)
- eco-python-ffmpeg-7-minimal-devAll versions (No fix recorded)
Wolfi4 products
- ffmpeg-7All versions (No fix recorded)
- ffmpeg-7.1All versions (No fix recorded)
- ffmpeg-8.0All versions (No fix recorded)
- ffmpeg-8.1All versions (No fix recorded)
Ubuntu2 products
- ffmpegAll versions (No fix recorded) | < 7:4.2.7-0ubuntu0.1+esm17 | < 7:4.4.2-0ubuntu0.22.04.1+esm16
- libavAll versions (No fix recorded)
Debian1 product
- ffmpegAll versions (No fix recorded) | < 7:9.0.2-1
Ffmpeg1 product
- ffmpeg≥ 0.5, < 9.0 | ≥ 0.5, < 9
5 vendors · 26 products
References
12 links- www.vulncheck.com/advisories/ffmpeg-uninitialized-heap-memory-read-in-tiff-decoderThird Party AdvisoryAdvisoryPatch
