Read the docs
TI-2021-20491 Aliases CVE-2021-45340GHSA-7xr9-9g9p-xmfp

In Libsixel prior to and including v1.10.3, a NULL pointer dereference in the stb_image.h…

Priority LOW 31CWE-476Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Required
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
No fix listed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-476.

Summary

In Libsixel prior to and including v1.10.3, a NULL pointer dereference in the stb_image.h component of libsixel allows attackers to cause a denial of service (DOS) via a crafted PICT file.

Why it matters now

EPSS 0.00918 60th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix No fix listed No fixed version in the sources yet

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
——all versions—No fix listedCNA
  • — Vendor— Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:libsixel:libsixel:*:*:*:*:*:*:*:*up to 1.10.3VulnerableLibsixel
  • cpe:2.3:a:libsixel:libsixel:*:*:*:*:*:*:*:* Versions up to 1.10.3 Vulnerable ·Libsixel

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-45340
  2. 2026-10-03 Alias added: GHSA-7xr9-9g9p-xmfp

References

Exploit 1

  • TI-2021-18385 libsixel 1.10.0 is vulnerable to Use after free in libsixel/src/dither.c:379. CVSS 3.1HIGH 8.8
  • TI-2021-17633 libsixel before 1.10 is vulnerable to Buffer Overflow in libsixel/src/quant.c:867. CVSS 3.1HIGH 8.8
  • TI-2022-10806 stb_image.h (aka the stb image loader) 2.19, as used in libsixel and other products, has… CVSS 3.1MEDIUM 5.5

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences