Vulnerability Description
libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. Versions 1.8.7 and prior contain an integer overflow leading to an out-of-bounds heap read in the --crop option handling of img2sixel, where positive coordinates up to INT_MAX are accepted without overflow-safe bounds checking. In sixel_encoder_do_clip(), the expression clip_w + clip_x overflows to a large negative value when clip_x is INT_MAX, causing the bounds guard to be skipped entirely, and the unclamped coordinate is passed through sixel_frame_clip() to clip(), which computes a source pointer far beyond the image buffer and passes it to memmove(). An attacker supplying a specially crafted crop argument with any valid image can trigger an out-of-bounds read in the heap, resulting in a reliable crash and potential information disclosure. This issue has been fixed in version 1.8.7-r1.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Saitoha | Libsixel | < 1.8.7-r1 |
Related Weaknesses (CWE)
References
- https://github.com/saitoha/libsixel/releases/tag/v1.8.7-r1Release Notes
- https://github.com/saitoha/libsixel/security/advisories/GHSA-c854-ffg9-g72cExploitVendor Advisory
- https://github.com/saitoha/libsixel/security/advisories/GHSA-c854-ffg9-g72cExploitVendor Advisory
FAQ
What is CVE-2026-33019?
CVE-2026-33019 is a vulnerability with a CVSS score of 7.1 (HIGH). libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. Versions 1.8.7 and prior contain an integer overflow leading to an out-of-bounds heap read in the --crop option handling ...
How severe is CVE-2026-33019?
CVE-2026-33019 has been rated HIGH with a CVSS base score of 7.1/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-33019?
Check the references section above for vendor advisories and patch information. Affected products include: Saitoha Libsixel.