CVE-2026-40930: CWE-436: Interpretation Conflict in pnggroup libpng
CVE-2026-40930 is a medium severity vulnerability in libpng version 1. 8. 0 where certain inter-frame chunk discard paths in the APNG parser clear the chunk-header flag without consuming the chunk body and CRC. This allows attacker-controlled bytes in an ignored ancillary chunk to be misinterpreted as a new chunk header on subsequent processing calls. The issue is fixed in commit faf06924688b62d7c1654b5ceddedbde66ffadb4. No known exploits are reported in the wild.
AI Analysis
Technical Summary
The vulnerability in libpng 1.8.0 involves three inter-frame chunk discard paths in the push-mode APNG parser. These paths clear the chunk-header flag prematurely without consuming the chunk body and CRC, enabling attacker-controlled data within an ignored ancillary chunk to be reinterpreted as a fresh chunk header during the next invocation of png_process_data. This interpretation conflict (CWE-436) can lead to incorrect processing of PNG data. The issue has been addressed by a specific commit that corrects this behavior.
Potential Impact
The vulnerability can cause libpng to misinterpret attacker-controlled data as new chunk headers, potentially leading to incorrect image processing and denial of service conditions. The CVSS score of 5.4 reflects a medium severity with no confidentiality impact, limited integrity impact, and low availability impact. There are no known exploits in the wild at this time.
Mitigation Recommendations
A fix for this vulnerability is available in the form of commit faf06924688b62d7c1654b5ceddedbde66ffadb4. Users of libpng version 1.8.0 should upgrade to a version that includes this commit or apply the patch directly. Since no official vendor advisory or patch link is provided, users should consult the libpng project repository or maintainers for the updated version containing this fix. Patch status is not yet confirmed by a vendor advisory; check the official libpng sources for current remediation guidance.
CVE-2026-40930: CWE-436: Interpretation Conflict in pnggroup libpng
Description
CVE-2026-40930 is a medium severity vulnerability in libpng version 1. 8. 0 where certain inter-frame chunk discard paths in the APNG parser clear the chunk-header flag without consuming the chunk body and CRC. This allows attacker-controlled bytes in an ignored ancillary chunk to be misinterpreted as a new chunk header on subsequent processing calls. The issue is fixed in commit faf06924688b62d7c1654b5ceddedbde66ffadb4. No known exploits are reported in the wild.
CVSS v3.1
Score 5.4medium
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in libpng 1.8.0 involves three inter-frame chunk discard paths in the push-mode APNG parser. These paths clear the chunk-header flag prematurely without consuming the chunk body and CRC, enabling attacker-controlled data within an ignored ancillary chunk to be reinterpreted as a fresh chunk header during the next invocation of png_process_data. This interpretation conflict (CWE-436) can lead to incorrect processing of PNG data. The issue has been addressed by a specific commit that corrects this behavior.
Potential Impact
The vulnerability can cause libpng to misinterpret attacker-controlled data as new chunk headers, potentially leading to incorrect image processing and denial of service conditions. The CVSS score of 5.4 reflects a medium severity with no confidentiality impact, limited integrity impact, and low availability impact. There are no known exploits in the wild at this time.
Mitigation Recommendations
A fix for this vulnerability is available in the form of commit faf06924688b62d7c1654b5ceddedbde66ffadb4. Users of libpng version 1.8.0 should upgrade to a version that includes this commit or apply the patch directly. Since no official vendor advisory or patch link is provided, users should consult the libpng project repository or maintainers for the updated version containing this fix. Patch status is not yet confirmed by a vendor advisory; check the official libpng sources for current remediation guidance.
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: 6/4/2026, 3:48:58 PM
Last enriched: 6/4/2026, 4:03:55 PM
Last updated: 6/4/2026, 5:04:13 PM
Views: 3
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