Application crash via reused FLAC frame buffer
Published Mar 23, 2022 · Updated Dec 11, 2025
Out-of-bounds read in libsndfile's FLAC codec allows remote attackers to crash linked applications via crafted audio files. flac_buffer_copy trusts a decoded frame's block size while reusing a prior callback buffer without tracking whether that buffer is large enough. Exploitation requires a consuming application to open and read the crafted FLAC content; documented effects include adjacent heap-data exposure and, most often, an application crash.
Summary
What happened
Out-of-bounds read in libsndfile's FLAC codec allows remote attackers to crash linked applications via crafted audio files. flac_buffer_copy trusts a decoded frame's block size while reusing a prior callback buffer without tracking whether that buffer is large enough. Exploitation requires a consuming application to open and read the crafted FLAC content; documented effects include adjacent heap-data exposure and, most often, an application crash.
The record
- CVE
- CVE-2021-4156
- Published
- Mar 23, 2022
- Updated
- Dec 11, 2025
- Vendor
- libsndfile Project
- Product
- libsndfile
- Classifications
- CWE-125, T1203
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 23, 2022CVE publishedPublication date reported by the CVE source.
- Dec 11, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=libsndfile 1.1.0
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
- heap_overflow_pocproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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