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Memory Buffer Bounds ErrorWeakness · CWE-119

CVE-2026-5236

MEDIUM · 5.3 CVSS v3.1 Published 2026-03-31
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
55/100
Remediation priority · Elevated
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A vulnerability was identified in Axiomatic Bento4 up to 1.6.0-641. Affected is the function AP4_BitReader::SkipBits of the file Ap4Dac4Atom.cpp of the component DSI v1 Parser. Such manipulation of the argument n_presentations leads to heap-based buffer overflow. The attack needs to be performed locally. The exploit is publicly available and might be used. The project was informed of the problem early through an issue report but has not responded yet.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Heap-based buffer overflow vulnerability in Bento4's DSI v1 Parser (Ap4Dac4Atom.cpp) in the AP4_BitReader::SkipBits function. By manipulating the n_presentations argument, an attacker can cause memory corruption on the heap, potentially leading to code execution. The vulnerability is locally exploitable and a public exploit exists.

MitigationImplement bounds checking in AP4_BitReader::SkipBits to validate the n_presentations parameter before reading/writing heap memory. Consider adding input validation in the DSI v1 parser to reject malformed streams before they reach the vulnerable function.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
Low

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify if Bento4 is installed
    Search for Bento4 libraries or tools on the system. Common file patterns: libap4*, Ap4*. On Linux: find / -name 'libap4*' 2>/dev/null. On Windows: search for Ap4*.dll in common install directories.
    Affected if Bento4 components are found on the system
  2. Determine Bento4 library version
    Check version information in library files or associated metadata. Use commands like: strings libap4.so | grep -i version, or check VERSION files, or run: mp4info --version if the Bento4 tools are installed.
    Affected if Installed version matches or predates the vulnerable version range for this CVE
  3. Locate the vulnerable DSI parser component
    Verify presence of Ap4Dac4Atom.cpp compiled object or the Ap4Dac4Atom functionality within the library. On Linux: nm libap4.so | grep -i Dac4. On Windows: dumpbin /SYMBOLS Ap4.dll | findstr Dac4.
    Affected if The Ap4Dac4Atom component (DSI v1 Parser) is present in the installed build
  4. Check if DSI parsing is invoked
    Review application logs, configuration, or source code that uses Bento4 for MP4 parsing. Look for code paths that parse DSI (Decoding Specific Information) atoms, particularly in MPEG-DASH or streaming contexts where DSI v1 parsing occurs.
    Affected if The application processes MP4/MPEG streams using Bento4's DSI parser functionality
  5. Verify heap allocation behavior during DSI parsing
    If source is available, inspect AP4_BitReader::SkipBits in Ap4Dac4Atom.cpp for bounds validation. Check whether n_presentations parameter is validated before heap operations.
    Affected if The SkipBits function lacks proper bounds checking on the n_presentations argument, allowing heap overflow

A user is affected if they have Bento4 installed with the Ap4Dac4Atom component and process media files that trigger the vulnerable DSI v1 parser code path without bounds checking on the n_presentations parameter.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Implement bounds checking in AP4_BitReader::SkipBits to validate the n_presentations parameter before reading/writing heap memory. Consider adding input validation in the DSI v1 parser to reject malformed streams before they reach the vulnerable function.

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing4.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,900
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-5236 in production — separate from our analysis above.

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