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Fencer Vulns
high 8.1

CVE-2026-75146 json

FFmpeg Out-of-Bounds Read in DASH Demuxer via dashdec.c

published 2026-08-19 2 mo ago modified 2026-10-27 13 d ago also EUVD-2026-62583

cvss
8.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 18%
public exploits
0
none known

Summary

FFmpeg before commit 65b0dab contains an out-of-bounds read in the DASH demuxer (libavformat/dashdec.c). When a live DASH manifest is refreshed with a startNumber that is lower than the previous value, the current sequence number is driven negative. The fragment retrieval function checked only the upper bound before indexing the fragments array, allowing a negative index to be used and causing an out-of-bounds read. A malicious or misconfigured DASH server can trigger this by serving a live manifest with a decreasing startNumber across a manifest refresh.

Patch / fix

  • ffmpeg Debian 14 7:9.0.2-1

debian advisories DEBIAN-CVE-2026-75146

  • ffmpeg Ubuntu Pro 18.04 LTS 7:3.4.11-0ubuntu0.1+esm15
  • ffmpeg Ubuntu Pro 20.04 LTS 7:4.2.7-0ubuntu0.1+esm16
  • ffmpeg Ubuntu Pro 22.04 LTS 7:4.4.2-0ubuntu0.22.04.1+esm15
  • ffmpeg Ubuntu Pro 24.04 LTS 7:6.1.1-3ubuntu5+esm13
  • ffmpeg Ubuntu Pro 26.04 LTS 7:8.0.1-3ubuntu2+esm4

ubuntu advisories UBUNTU-CVE-2026-75146

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • ffmpeg-4 SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE High Performance Computing 15 SP4-LTSS +1 more 4.4.8-150400.3.75.1
  • ffmpeg-4 SLE Workstation Extension 15 SP7, SLE Module for Package Hub 15 SP7 4.4.8-150600.13.55.1

suse advisories SUSE-SU-2026:4150-1SUSE-SU-2026:4149-1

  • ffmpeg-7 openSUSE Leap 16.0 7.1.5-160000.1.1
  • ffmpeg-4 openSUSE Tumbleweed 4.4.8-5.1
  • ffmpeg-8 openSUSE Tumbleweed 8.1.2-3.1
  • ffmpeg-7 openSUSE Tumbleweed 7.1.5-2.1
  • ffmpeg-9 openSUSE Tumbleweed 9.0.1-3.1

opensuse advisories openSUSE-SU-2026:21877-1openSUSE-SU-2026:11716-1openSUSE-SU-2026:11682-1openSUSE-SU-2026:11665-1openSUSE-SU-2026:11659-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-75146 updated cvss 8.1

ffmpeg: FFmpeg: Information disclosure and denial of service via out-of-bounds read in DASH demuxer

  • Red Hat OpenShift AI (RHOAI) rhoai/odh-vllm-gaudi-rhel9
    affected: workaround, no fix available “No mitigation is currently available for this flaw.”
  • Red Hat Enterprise Linux AI 3.5 for RHEL 9 ffmpeg 6.1.6-10.el9ai, ffmpeg-free-rhai 6.1.6-10.el9ai, libavutil-free-rhai 6.1.6-10.el9ai, libavcodec-free-rhai 6.1.6-10.el9ai, libswscale-free-rhai 6.1.6-10.el9ai, libavdevice-free-rhai 6.1.6-10.el9ai, +4 more
    fixed: vendor fix “No mitigation is currently available for this flaw.” RHSA-2026:94488

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 mo ago

Exploit prediction

0.26% chance of exploitation in the next 30 days, higher than 18% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 7.2 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:H/SC:N/SI:N/SA:N
CNA 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H
CNA 4.0 7.2 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:H/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

Affected products

  • FFmpeg FFmpeg

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.