CVE-2026-27809
psd-tools: Compression module has unguarded zlib decompression, missing dimension validation, and hardening gaps
Description
psd-tools is a Python package for working with Adobe Photoshop PSD files. Prior to version 1.12.2, when a PSD file contains malformed RLE-compressed image data (e.g. a literal run that extends past the expected row size), decode_rle() raises ValueError which propagated all the way to the user, crashing psd.composite() and psd-tools export. decompress() already had a fallback that replaces failed channels with black pixels when result is None, but it never triggered because the ValueError from decode_rle() was not caught. The fix in version 1.12.2 wraps the decode_rle() call in a try/except so the existing fallback handles the error gracefully.
How to fix CVE-2026-27809
To remediate CVE-2026-27809, upgrade the affected package to a fixed version below.
- —no fix listed
- —upgrade to 1.12.2 or later
Is CVE-2026-27809 being exploited?
Low — EPSS is 0.1%, meaning exploitation activity has not been observed at scale.
Affected packages (2)
- from 0
- from 0, < 1.12.2
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N/E:U |
| osv | CVSS 3.1 | CRITICAL9.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H |