CVE-2026-73639
Description
Imager::File::PNG versions from 1.003 before 1.004 for Perl write past the end of the row buffer reading a PNG with a tRNS transparency chunk in read_direct8. With a tRNS chunk, read_direct8() adds an alpha channel to the image it creates but still sizes the row buffer from the original channel count. libpng expands the transparency into that extra channel, so png_read_row() fills one channel more than the buffer holds, at one byte per sample, and writes width bytes past the end of the allocation. Palette images go to read_paletted() and 16-bit images to read_direct16(), which sizes its buffer from png_get_rowbytes() and allocates enough for the expanded row. The same reader ships bundled in the Imager distribution. Reading an attacker-supplied PNG through Imager->read() corrupts the heap, which can crash the process.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
Propose a mitigation on Community Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
Debian Mixed 5 releases
| Version | Status | Fixed in |
|---|---|---|
| trixie | Affected | — |
| sid | Fixed | 1.035+dfsg-1 |
| forky | Fixed | 1.035+dfsg-1 |
| bullseye | Affected | — |
| bookworm | Affected | — |
References
- https://security-tracker.debian.org/tracker/CVE-2026-73639
- https://github.com/tonycoz/imager/commit/d973bd7e8843f084e8071caa24b89545c88b1e4b.patch
- https://github.com/tonycoz/imager/pull/567
- https://github.com/tonycoz/imager/security/advisories/GHSA-jhx5-34j8-9g88
- https://metacpan.org/release/TONYC/Imager-1.035/changes
- https://metacpan.org/release/TONYC/Imager-File-PNG-1.004/changes
- http://www.openwall.com/lists/oss-security/2026/09/17/6
CWEs
CWE-787
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.