Vulnerability · Published Apr 8, 2022 · Assigned by mitre

CVE-2021-40656

High 8.8

In plain English

A high-severity security flaw in the libsixel package (Debian). There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.0% (higher than 64% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS NVD)8.8High
Exploit odds (30 days)1.0%top 36.5% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known

Official description

libsixel before 1.10 is vulnerable to Buffer Overflow in libsixel/src/quant.c:867.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12libsixel1.10.3-1DEBIAN-CVE-2021-40656
Debian:13libsixel1.10.3-1DEBIAN-CVE-2021-40656
Debian:14libsixel1.10.3-1DEBIAN-CVE-2021-40656
Ubuntu:22.04:LTSlibsixelno fix listedUBUNTU-CVE-2021-40656
Ubuntu:24.04:LTSlibsixelno fix listedUBUNTU-CVE-2021-40656
Ubuntu:25.10libsixelno fix listedUBUNTU-CVE-2021-40656
Ubuntu:26.04:LTSlibsixelno fix listedUBUNTU-CVE-2021-40656
Ubuntu:26.10libsixelno fix listedUBUNTU-CVE-2021-40656

Affected products (as reported)

VendorProductVersions
n/a n/a n/a

References