CVE-2021-40656: libsixel Out-of-bounds Write
CVSS: 8.8v3.1HighAnalyzed
AliasesUBUNTU-CVE-2021-40656DEBIAN-CVE-2021-40656
Published 08-04-2022Last modified 04-08-2024
Vulnerability summary
CVE-2021-40656 is a high (CVSS 8.8) Out-of-bounds Write vulnerability in libsixel. EPSS estimates a 1.02% chance of exploitation in the next 30 days, higher than 62.7% of scored vulnerabilities. 1 public exploit is recorded.
CVSS score
8.8/10
010
High · v3.1 (NVD)EPSS score
1.02%
0%100%
Low · 0.00 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits1github
Timeline
- 08-04-2022PublishedVulnerability first disclosed.
- 04-08-2024Last modifiedVulnerability information updated.
Description
libsixel before 1.10 is vulnerable to Buffer Overflow in libsixel/src/quant.c:867.
CVSS metrics
4 scores · 3 sources · 2 versionsHigh 8.8Preferred score · NVD (NIST)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HSourcesAll 3 agree
- OSV · UbuntuEcosystem advisory · calculated8.8HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated8.8HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Medium 6.8Preferred score · NVD (NIST)
AV:N/AC:M/Au:N/C:P/I:P/A:PSourcesSingle source
EPSS trend
Probability
1.02%
Chance of exploitation in the next 30 days
Percentile
63%
Versus all other CVEs
30-day change
0.00 pp
From 1.02% on 19-09-2026
19-09-202619-10-2026
EPSS score1.02%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
1 foundLibsixel
Maturity: poc
Weaknesses
CWE · root causeAffected systems
Debian1 product
- libsixel< 1.10.3-1
Libsixel1 product
- libsixel< 1.10.0
Ubuntu1 product
- libsixelAll versions (No fix recorded)
3 vendors · 3 products
References
4 links- github.com/libsixel/libsixel/issues/25X Refsource MISCREPORTExploitIssue TrackingThird Party Advisory
