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CVE detail

CVE-2026-33416

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 7.5 · HighBuzz score 35.31 public exploit repository references

Buzz score

Why this CVE is surfacing

Buzz score total 35.3

This all-time snapshot uses the same composite formula as Trending across a 30-year evidence window, rather than a current rolling window.

Buzz score components · mention 20.8 · diversity 10.0 · KEV 0.0 · OTX 0.0 · PoC 4.5
Mention score
20.8
7 evidence mentions in the snapshot
Diversity score
10.0
2 sources across 2 categories
KEV score
0.0
No KEV entry observed
OTX score
0.0
0 OTX pulses
PoC score
4.5
1 repos · best confidence 0.90
Best PoC traction
0
Maximum stars on a matched PoC repo

Why it matters now

Mention timeline

Total mentions
0
within the 30d window
Peak daily
0
highest bucket

Evidence

Source links by recency

Newest mentions first
7 source links · newest first

Exploit code

Public exploit repository references

Public PoC repositories are third-party, potentially unsafe artifacts. Treat their code as untrusted and use it only on authorized systems in an isolated, least-privilege environment. cvebuzz does not execute the code or verify that an exploit works.

1 repository references · best confidence 0.90 · max 0 stars
  • pnggroup/libpngHigh confidence
    githubNVD Exploit reference0 starsDiscovered Jul 12, 2026, 12:20 AM

    NVD labels the source link as Exploit; this is not independent verification of the repository's code.

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