Vulnerability · Published Sep 17, 2026 · Assigned by CPANSec
CVE-2026-73639Imager::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
Critical 9.1
In plain English
A critical-severity out-of-bounds write in Imager. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 53% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | libimager-perl | no fix listed | DEBIAN-CVE-2026-73639 |
| Debian:13 | libimager-perl | no fix listed | DEBIAN-CVE-2026-73639 |
| Debian:14 | libimager-perl | 1.035+dfsg-1 | DEBIAN-CVE-2026-73639 |
| Ubuntu:22.04:LTS | libimager-perl | no fix listed | UBUNTU-CVE-2026-73639 |
| Ubuntu:24.04:LTS | libimager-perl | no fix listed | UBUNTU-CVE-2026-73639 |
| Ubuntu:26.04:LTS | libimager-perl | no fix listed | UBUNTU-CVE-2026-73639 |
| Ubuntu:26.10 | libimager-perl | no fix listed | UBUNTU-CVE-2026-73639 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Imager-File-PNG | 1.003 – before 1.004 | |
| Imager | 1.034 – before 1.035 |
Weakness: CWE-787 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
References
- https://github.com/tonycoz/imager/security/advisories/GHSA-jhx5-34j8-9g88 vendor-advisory
- https://github.com/tonycoz/imager/commit/d973bd7e8843f084e8071caa24b89545c88b1e4b.patch patch
- https://github.com/tonycoz/imager/pull/567 issue-tracking
- https://metacpan.org/release/TONYC/Imager-File-PNG-1.004/changes release-notes
- https://metacpan.org/release/TONYC/Imager-1.035/changes release-notes
- http://www.openwall.com/lists/oss-security/2026/09/17/6