CVE-2026-34757: CWE-416: Use After Free in pnggroup libpng
A use-after-free vulnerability exists in libpng versions from 1. 0. 9 up to but not including 1. 6. 57. This occurs when pointers obtained from certain getter functions are passed back into their corresponding setter functions on the same png_struct/png_info pair, causing the setter to read from freed memory. The freed memory may contain stale or unrelated heap data, leading to silent corruption of chunk metadata or leakage of unrelated heap contents. This vulnerability has a CVSS score of 5. 1 (medium severity) and is fixed in libpng version 1. 6.
AI Analysis
Technical Summary
The vulnerability in libpng (CVE-2026-34757) involves a use-after-free condition triggered when a pointer obtained from png_get_PLTE, png_get_tRNS, or png_get_hIST is passed back into the corresponding setter on the same png_struct/png_info pair. The setter frees its internal buffer before copying from the caller-supplied pointer, which points to freed memory. This can cause the setter to copy stale or unrelated heap data into the replacement buffer, potentially corrupting PNG chunk metadata or leaking unrelated heap contents. The issue affects libpng versions from 1.0.9 up to but not including 1.6.57 and is resolved in version 1.6.57.
Potential Impact
Successful exploitation can lead to silent corruption of PNG chunk metadata or leakage of unrelated heap contents. The CVSS vector indicates the attack requires local access (AV:L), low complexity (AC:L), no privileges (PR:N), and no user interaction (UI:N). The impact on confidentiality and integrity is low, with no impact on availability. There are no known exploits in the wild at this time.
Mitigation Recommendations
This vulnerability is fixed in libpng version 1.6.57. Users and developers should upgrade to version 1.6.57 or later to remediate this issue. Patch status is confirmed by the version fix information. No additional mitigation steps are indicated.
CVE-2026-34757: CWE-416: Use After Free in pnggroup libpng
Description
A use-after-free vulnerability exists in libpng versions from 1. 0. 9 up to but not including 1. 6. 57. This occurs when pointers obtained from certain getter functions are passed back into their corresponding setter functions on the same png_struct/png_info pair, causing the setter to read from freed memory. The freed memory may contain stale or unrelated heap data, leading to silent corruption of chunk metadata or leakage of unrelated heap contents. This vulnerability has a CVSS score of 5. 1 (medium severity) and is fixed in libpng version 1. 6.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in libpng (CVE-2026-34757) involves a use-after-free condition triggered when a pointer obtained from png_get_PLTE, png_get_tRNS, or png_get_hIST is passed back into the corresponding setter on the same png_struct/png_info pair. The setter frees its internal buffer before copying from the caller-supplied pointer, which points to freed memory. This can cause the setter to copy stale or unrelated heap data into the replacement buffer, potentially corrupting PNG chunk metadata or leaking unrelated heap contents. The issue affects libpng versions from 1.0.9 up to but not including 1.6.57 and is resolved in version 1.6.57.
Potential Impact
Successful exploitation can lead to silent corruption of PNG chunk metadata or leakage of unrelated heap contents. The CVSS vector indicates the attack requires local access (AV:L), low complexity (AC:L), no privileges (PR:N), and no user interaction (UI:N). The impact on confidentiality and integrity is low, with no impact on availability. There are no known exploits in the wild at this time.
Mitigation Recommendations
This vulnerability is fixed in libpng version 1.6.57. Users and developers should upgrade to version 1.6.57 or later to remediate this issue. Patch status is confirmed by the version fix information. No additional mitigation steps are indicated.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-03-30T19:17:10.225Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 69d7bccb1cc7ad14dad7b12a
Added to database: 4/9/2026, 2:50:51 PM
Last enriched: 4/9/2026, 3:06:58 PM
Last updated: 4/9/2026, 4:13:37 PM
Views: 3
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