CVE-2026-40930: CWE-436: Interpretation Conflict in pnggroup libpng
A vulnerability in libpng version 1.8.0 involves an interpretation conflict in the APNG parser's handling of ancillary chunks. Specifically, certain discard paths clear the chunk-header flag without consuming the chunk body and CRC, which may allow attacker-controlled data to be misinterpreted as new chunk headers. This issue is identified as CWE-436 and has a CVSS score of 5.4, indicating medium severity.
AI Analysis
Technical Summary
In libpng 1.8.0, three inter-frame chunk discard paths in the push-mode APNG parser improperly clear the chunk-header flag without consuming the chunk body and CRC. This flaw allows attacker-controlled bytes inside an ignored ancillary chunk to be reinterpreted as a fresh chunk header on subsequent calls to png_process_data. The vulnerability is classified under CWE-436 (Interpretation Conflict). A commit (faf06924688b62d7c1654b5ceddedbde66ffadb4) reportedly fixes the issue, but no official patch or remediation level is provided in the available data.
Potential Impact
The vulnerability can lead to incorrect processing of PNG data, potentially causing denial of service or other impacts related to application logic errors. The CVSS vector indicates the attack can be performed remotely with low attack complexity and no privileges required, but requires user interaction. The impact is limited to integrity and availability, with no confidentiality impact reported.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Although a fixing commit is referenced, no official patch or remediation level is documented. Users of libpng version 1.8.0 should monitor vendor channels for an official fix and consider avoiding use of this version until remediation is confirmed.
CVE-2026-40930: CWE-436: Interpretation Conflict in pnggroup libpng
Description
A vulnerability in libpng version 1.8.0 involves an interpretation conflict in the APNG parser's handling of ancillary chunks. Specifically, certain discard paths clear the chunk-header flag without consuming the chunk body and CRC, which may allow attacker-controlled data to be misinterpreted as new chunk headers. This issue is identified as CWE-436 and has a CVSS score of 5.4, indicating medium severity.
CVSS v3.1
Score 5.4medium
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
In libpng 1.8.0, three inter-frame chunk discard paths in the push-mode APNG parser improperly clear the chunk-header flag without consuming the chunk body and CRC. This flaw allows attacker-controlled bytes inside an ignored ancillary chunk to be reinterpreted as a fresh chunk header on subsequent calls to png_process_data. The vulnerability is classified under CWE-436 (Interpretation Conflict). A commit (faf06924688b62d7c1654b5ceddedbde66ffadb4) reportedly fixes the issue, but no official patch or remediation level is provided in the available data.
Potential Impact
The vulnerability can lead to incorrect processing of PNG data, potentially causing denial of service or other impacts related to application logic errors. The CVSS vector indicates the attack can be performed remotely with low attack complexity and no privileges required, but requires user interaction. The impact is limited to integrity and availability, with no confidentiality impact reported.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Although a fixing commit is referenced, no official patch or remediation level is documented. Users of libpng version 1.8.0 should monitor vendor channels for an official fix and consider avoiding use of this version until remediation is confirmed.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-04-15T20:40:15.518Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a219e6ae29bf47b50b44761
Added to database: 06/04/2026, 15:48:58 UTC
Last enriched: 06/24/2026, 17:20:54 UTC
Last updated: 07/31/2026, 19:22:58 UTC
Views: 136
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