CVE-2026-73639
Imager::File::PNG buffer overflow
- Published17 Sept 2026
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.
CVSS 3.1 breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:HRemediation
No fixed version is recorded in the NVD data. Check the vendor advisory for the latest guidance.
References
- 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
Related CVEs
Recent high-severity vulnerabilities sharing a weakness type.
Frequently asked
Is CVE-2026-73639 being actively exploited?
CVE-2026-73639 is not in the CISA KEV catalog. Its EPSS exploit probability is 0.70%.
How severe is CVE-2026-73639?
CVE-2026-73639 has a CVSS 3.1 base score of 9.1, rated critical. EPSS estimates a 0.70% probability of exploitation.
How do I fix CVE-2026-73639?
Apply the vendor's patch or advisory guidance, then verify no affected versions remain across your devices.
How Secuno handles this
Secuno correlates vulnerabilities like CVE-2026-73639 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.
Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.