Denial of Service in libsixel SIXEL Encoder/Decoder by Saitoha
CVE-2026-44638

2.5LOW

Key Information:

Vendor

Saitoha

Status
Libsixel
Vendor
CVE Published:
14 May 2026

What is CVE-2026-44638?

The libsixel SIXEL encoder/decoder, developed by Saitoha, is vulnerable to a denial of service due to a flaw in the allocation handling within the sixel_decode_raw and sixel_decode functions. A false negative in NULL checks following memory allocation can cause a NULL pointer dereference whenever memory allocation fails, leading to process termination. This issue occurs when the output parameter's address is checked instead of the actual value returned by the malloc operation. Consequently, when the system encounters low memory, the function proceeds incorrectly, writing through a NULL pointer and causing crashes. The vulnerability has been addressed in version 1.8.7-r2.

Affected Version(s)

libsixel >= 1.0.0, < 1.8.7-r2

References

https://github.com/saitoha/libsixel/security/advisories/G...
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CVSS V3.1

Score:
2.5
Severity:
LOW
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Local
Attack Complexity:
High
Privileges Required:
None
User Interaction:
Required
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.