CVE-2026-34757: CWE-416: Use After Free in pnggroup libpng
LIBPNG is a reference library for use in applications that read, create, and manipulate PNG (Portable Network Graphics) raster image files. From 1.0.9 to before 1.6.57, passing a pointer obtained from png_get_PLTE, png_get_tRNS, or png_get_hIST back into the corresponding setter on the same png_struct/png_info pair causes the setter to read from freed memory and copy its contents into the replacement buffer. The setter frees the internal buffer before copying from the caller-supplied pointer, which now dangles. The freed region may contain stale data (producing silently corrupted chunk metadata) or data from subsequent heap allocations (leaking unrelated heap contents into the chunk struct). This vulnerability is fixed in 1.6.57.
AI Analysis
Technical Summary
CVE-2026-34757 is a use-after-free vulnerability in libpng, a widely used library for handling PNG image files. Specifically, 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 results in reading stale or unrelated heap data, causing silent corruption of chunk metadata or leakage of unrelated heap contents. The vulnerability 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
The vulnerability can cause silent corruption of PNG chunk metadata or leakage of unrelated heap contents due to use-after-free memory access. The CVSS 3.1 score of 5.1 reflects a medium severity with limited confidentiality and integrity impact, and no availability impact. 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 not explicitly confirmed in the vendor advisory beyond the stated fix version, so users should verify with the official libpng release notes or vendor advisory for confirmation.
CVE-2026-34757: CWE-416: Use After Free in pnggroup libpng
Description
LIBPNG is a reference library for use in applications that read, create, and manipulate PNG (Portable Network Graphics) raster image files. From 1.0.9 to before 1.6.57, passing a pointer obtained from png_get_PLTE, png_get_tRNS, or png_get_hIST back into the corresponding setter on the same png_struct/png_info pair causes the setter to read from freed memory and copy its contents into the replacement buffer. The setter frees the internal buffer before copying from the caller-supplied pointer, which now dangles. The freed region may contain stale data (producing silently corrupted chunk metadata) or data from subsequent heap allocations (leaking unrelated heap contents into the chunk struct). This vulnerability is fixed in 1.6.57.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-34757 is a use-after-free vulnerability in libpng, a widely used library for handling PNG image files. Specifically, 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 results in reading stale or unrelated heap data, causing silent corruption of chunk metadata or leakage of unrelated heap contents. The vulnerability 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
The vulnerability can cause silent corruption of PNG chunk metadata or leakage of unrelated heap contents due to use-after-free memory access. The CVSS 3.1 score of 5.1 reflects a medium severity with limited confidentiality and integrity impact, and no availability impact. 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 not explicitly confirmed in the vendor advisory beyond the stated fix version, so users should verify with the official libpng release notes or vendor advisory for confirmation.
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: 5/10/2026, 1:41:17 AM
Last updated: 5/24/2026, 7:17:48 PM
Views: 84
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