{"cve":"CVE-2026-33416","nvd":{"published":"2026-03-26T17:16:38.443","modified":"2026-06-17T10:37:27.583","status":"Analyzed","description":"LIBPNG is a reference library for use in applications that read, create, and manipulate PNG (Portable Network Graphics) raster image files. In versions 1.2.1 through 1.6.55, `png_set_tRNS` and `png_set_PLTE` each alias a heap-allocated buffer between `png_struct` and `png_info`, sharing a single allocation across two structs with independent lifetimes. The `trans_alpha` aliasing has been present since at least libpng 1.0, and the `palette` aliasing since at least 1.2.1. Both affect all prior release lines `png_set_tRNS` sets `png_ptr->trans_alpha = info_ptr->trans_alpha` (256-byte buffer) and `png_set_PLTE` sets `info_ptr->palette = png_ptr->palette` (768-byte buffer). In both cases, calling `png_free_data` (with `PNG_FREE_TRNS` or `PNG_FREE_PLTE`) frees the buffer through `info_ptr` while the corresponding `png_ptr` pointer remains dangling. Subsequent row-transform functions dereference and, in some code paths, write to the freed memory. A second call to `png_set_tRNS` or `png_set_PLTE` has the same effect, because both functions call `png_free_data` internally before reallocating the `info_ptr` buffer. Version 1.6.56 fixes the issue.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H","score":7.5},"cwes":["CWE-416"],"references":["https://github.com/pnggroup/libpng/commit/23019269764e35ed8458e517f1897bd3c54820eb","https://github.com/pnggroup/libpng/commit/7ea9eea884a2328cc7fdcb3c0c00246a50d90667","https://github.com/pnggroup/libpng/commit/a3a21443ed12bfa1ef46fa0d4fb2b74a0fa34a25","https://github.com/pnggroup/libpng/commit/c1b0318b393c90679e6fa5bc1d329fd5d5012ec1","https://github.com/pnggroup/libpng/pull/824"],"products":["libpng:libpng"],"source":"nvd","synced_at":"2026-10-19T22:28:18.033120106+00:00"},"epss":{"cve":"CVE-2026-33416","score":0.01071,"percentile":0.64874,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}