Buffer overflow in Happyseafox Sail
CVE-2026-40493
SAIL is a cross-platform library for loading and saving images with support for animation, metadata, and ICC profiles. Prior to commit c930284445ea3ff94451ccd7a57c999eca3bc979, the PSD codec computes bytes-per-pixel (`bpp`) from raw header fields `channels * depth`, but the pixel buffer is allocated based on the resolved pixel format. For LAB mode with `channels=3, depth=16`, `bpp = (3*16+7)/8 = 6`, but the format `BPP40_CIE_LAB` allocates only 5 bytes per pixel. Every pixel write overshoots, causing a deterministic heap buffer overflow on every row. Commit c930284445ea3ff94451ccd7a57c999eca3bc979 contains a patch.
Vulnerability class: Buffer Overflow
EPSS: 0.004 (29.3th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
Affected products
- Happyseafox Sail — versions < c930284445ea3ff94451ccd7a57c999eca3bc979
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM)
- security-advisories@github.com (x_refsource_MISC)
Frequently asked questions
- What is CVE-2026-40493?
- CVE-2026-40493 is a critical-severity vulnerability in Happyseafox Sail, classified under Out-of-bounds Write. CVSS score: 9.8/10. Published 2026-04-18.
- How severe is CVE-2026-40493?
- Critical severity. CVSS v3 base score is 9.8 out of 10.