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Fencer Intel
high 8.8

CVE-2021-40656 json

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

published 4y ago modified 4mo ago also EUVD-2021-27830

cvss
8.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.0%
EPSS 1.0% chance of exploitation in 30 days, percentile 63%
public exploits
0
none known

Summary

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

Patch / fix

  • libsixel libsixel 1.10.0
  • libsixel Debian 14, Debian 13, Debian 12 1.10.3-1

debian advisories DEBIAN-CVE-2021-40656

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Exploit prediction

1.02% chance of exploitation in the next 30 days, higher than 63% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/libsixel/libsixel/issues/25 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
NVD 2.0 6.8 AV:N/AC:M/Au:N/C:P/I:P/A:P

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.