TI-2020-13975 Aliases CVE-2020-21049 GHSA-v6gq-6h27-8r9r

An invalid read in the stb_image.h component of libsixel prior to v1.8.5 allows attackers…

LOW 32CWE-125Published 2021-09-14 · Updated 2024-08-04

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-125 and the CVSS impact.

Summary

An invalid read in the stb_image.h component of libsixel prior to v1.8.5 allows attackers to cause a denial of service (DOS) via a crafted PSD file.

Why it matters now

EPSS 0.01376 72nd 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

Vendor	Product	Affected versions	Fixed in	Status	Source
—	—	all versions	—	No fix listed	CNA

— Vendor— Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:saitoha:libsixel::::::::	before 1.8.5	Vulnerable	saitoha

cpe:2.3:a:saitoha:libsixel:*:*:*:*:*:*:*:* Versions before 1.8.5 Vulnerable ·saitoha

Remediation

No fixed version listed by the sources yet.

Timeline

2026-10-02 Threatist record created from CVE-2020-21049
2026-10-03 Alias added: GHSA-v6gq-6h27-8r9r

References

Exploit 1

https://github.com/saitoha/libsixel/issues/74

Patch 1

https://github.com/saitoha/libsixel/commit/0b1e0b3f7b44233f84e5c9f512f8c90d6bbbe33d

Advisory 2

Other 1

https://bitbucket.org/netbsd/pkgsrc/commits/970a81d31ec7498e04d09b6b7771cef35f63cd28

TI-2026-32536 libsixel: integer overflow in encoder CVSS 3.1HIGH 7.8
TI-2026-25469 libsixel: Use-after-free in load_with_gdkpixbuf() CVSS 3.1HIGH 7.8
TI-2026-32537 libsixel: integer overflow in parser CVSS 3.1HIGH 7.1
TI-2026-25466 libsixel: Integer Overflow in write_png_to_file() leads to Heap-based Buffer Overflow CVSS 3.1HIGH 7.1
TI-2026-25464 libsixel: Use-After-Free in load_gif() CVSS 3.1HIGH 7.0
TI-2026-25467 libsixel: Use-after-free in sixel_encoder_encode_bytes() CVSS 3.1HIGH 7.3

See all 47 →

Sources

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