Integer overflow in Psd-Tools
CVE-2026-27809
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.
Vulnerability class: Integer Overflow
EPSS: 0.004 (33.6th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H.
Affected products
- Psd-tools — versions < 1.12.2
- Psd-tools_project Psd-tools
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Exploit, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC)
- security-advisories@github.com (Product, x_refsource_MISC, Release Notes)
Frequently asked questions
- What is CVE-2026-27809?
- CVE-2026-27809 is a critical-severity vulnerability in Psd-Tools, classified under Integer Overflow or Wraparound. CVSS score: 9.1/10. Published 2026-02-26.
- How severe is CVE-2026-27809?
- Critical severity. CVSS v3 base score is 9.1 out of 10.