CVE-2026-52297: FFmpeg Buffer Overflow Vulnerability

CVE-2026-52297 is a buffer overflow flaw in FFmpeg affecting versions before 9.0, caused by inadequate padding in MOV file parsing. This vulnerability enables out-of-bounds memory reads during media processing. This post covers technical details, affected versions, impact assessment, and mitigation strategies.

CVE-2026-52297 Overview

CVE-2026-52297 is an out-of-bounds read vulnerability in FFmpeg versions before 9.0. The flaw resides in the mov_read_iacb function within libavformat/mov.c, which handles MOV container parsing. Insufficiently padded extradata allows the parser to read memory beyond the intended buffer boundary during processing of crafted MOV files.

The vulnerability is classified as an Out-of-Bounds Read [CWE-125] and requires local access with high attack complexity. Exploitation impacts availability only, with no direct effect on confidentiality or integrity. FFmpeg addressed the issue in version 9.0 through a commit that adjusts extradata padding in the affected code path.

Critical Impact
A local attacker can trigger an out-of-bounds read in mov_read_iacb, potentially causing FFmpeg to crash when processing a malformed MOV file.

Affected Products

FFmpeg versions prior to 9.0
Applications and services embedding vulnerable libavformat builds
Media processing pipelines invoking MOV parsing through FFmpeg

Discovery Timeline

2026-09-13 - CVE-2026-52297 published to the National Vulnerability Database
2026-09-14 - Last updated in NVD database

Technical Details for CVE-2026-52297

Vulnerability Analysis

The vulnerability affects the MOV demuxer in FFmpeg's libavformat library. The mov_read_iacb function parses the Immersive Audio Container Box (IACB) atom within MOV files. During parsing, the function reads extradata associated with the IACB atom but does not ensure the buffer has sufficient trailing padding.

FFmpeg typically requires AV_INPUT_BUFFER_PADDING_SIZE bytes of zero-padding after decoder input buffers to allow bitstream readers to safely read past the nominal end of data. When this padding is missing or undersized, subsequent read operations access adjacent, uninitialized, or unmapped memory.

The fix, delivered in FFmpeg Commit #8439e02, corrects the padding handling in the affected parsing path.

Root Cause

The root cause is insufficient buffer padding on extradata processed by mov_read_iacb. Downstream bitstream reader routines assume a padded tail region and read beyond the allocated bytes. This produces an out-of-bounds read classified under [CWE-125].

Attack Vector

An attacker must supply a crafted MOV file to a local FFmpeg process. The attack requires local access, has high complexity, and no user interaction. Successful exploitation causes a read past buffer bounds, which most commonly results in a process crash or unpredictable parser behavior. No arbitrary code execution has been demonstrated for this issue.

Refer to the GitHub Vulnerabilities Reference for the reproduction context.

Detection Methods for CVE-2026-52297

Indicators of Compromise

Unexpected FFmpeg process crashes or SIGSEGV terminations when handling MOV inputs
Media conversion or transcoding jobs failing on specific MOV files containing IACB atoms
Sanitizer reports (AddressSanitizer) flagging out-of-bounds reads in mov_read_iacb

Detection Strategies

Inventory FFmpeg and libavformat versions across build systems, media servers, and workstations to identify installations below 9.0
Scan third-party applications that statically link or bundle FFmpeg for vulnerable versions
Run fuzzing or sanitizer-enabled test builds against MOV samples containing IACB atoms

Monitoring Recommendations

Alert on abnormal termination signals from media processing services and transcoding workers
Log and review MOV files that trigger parser failures for potential malicious crafting
Track advisories from downstream Linux distributions repackaging FFmpeg 9.0

How to Mitigate CVE-2026-52297

Immediate Actions Required

Upgrade FFmpeg to version 9.0 or later on all affected systems
Rebuild and redeploy applications that statically link vulnerable libavformat versions
Restrict MOV inputs to trusted sources until patched builds are deployed

Patch Information

The issue is resolved in FFmpeg 9.0 through the upstream fix referenced in FFmpeg Pull Request #22988 and applied in FFmpeg Commit #8439e02. Downstream package maintainers should backport this commit to supported LTS branches.

Workarounds

Disable or block MOV parsing paths in media pipelines that do not require IACB handling
Sandbox FFmpeg execution using seccomp, containers, or dedicated low-privilege service accounts
Validate MOV inputs with size and format checks before submitting them to FFmpeg

bash

# Verify installed FFmpeg version and upgrade if below 9.0
ffmpeg -version | head -n 1

# Example: build FFmpeg 9.0 from source with sandbox-friendly options
git clone https://git.ffmpeg.org/ffmpeg.git ffmpeg && cd ffmpeg
git checkout n9.0
./configure --prefix=/usr/local --disable-debug --enable-hardcoded-tables
make -j"$(nproc)" && sudo make install