CVE-2026-33019

Summary

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.

Affected Software

VendorProductVersion RangeStatus
saitohalibsixel< 1.8.7-r1affected

Weaknesses

  • CWE-125: CWE-125: Out-of-bounds Read
  • CWE-190: CWE-190: Integer Overflow or Wraparound

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: poc
    • Automatable: no
    • Technical Impact: partial

Additional References

References