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Fencer Vulns
high 7.5

CVE-2021-20309 json

A flaw was found in ImageMagick in versions before 7.0.11 and before 6.9.12, where a division by zero in WaveImage() of MagickCore/visual-e…

published 2021-05-11 5 y ago modified 2026-07-30 3 mo ago also EUVD-2021-7734 , JLSEC-2026-884

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.3%
EPSS 2.3% chance of exploitation in 30 days, percentile 83%
public exploits
0
none known

Summary

A flaw was found in ImageMagick in versions before 7.0.11 and before 6.9.12, where a division by zero in WaveImage() of MagickCore/visual-effects.c may trigger undefined behavior via a crafted image file submitted to an application using ImageMagick. The highest threat from this vulnerability is to system availability.

Patch / fix

  • julia ImageMagick_jll 6.9.12+0
  • imagemagick imagemagick 6.9.12, 7.0.11-0
  • imagemagick Debian 14, Debian 13, Debian 12 8:6.9.11.60+dfsg-1.5

debian advisories DEBIAN-CVE-2021-20309

  • imagemagick Ubuntu 18.04 LTS 8:6.9.7.4+dfsg-16ubuntu6.12
  • imagemagick Ubuntu 20.04 LTS 8:6.9.10.23+dfsg-2.1ubuntu11.9
  • imagemagick Ubuntu Pro 14.04 LTS 8:6.7.7.10-6ubuntu3.13+esm1
  • imagemagick Ubuntu Pro 16.04 LTS 8:6.8.9.9-7ubuntu5.16+esm1
  • imagemagick Ubuntu Pro 22.04 LTS 8:6.9.11.60+dfsg-1.3ubuntu0.22.04.1+esm1

ubuntu advisories UBUNTU-CVE-2021-20309

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • ImageMagick SLES for SAP 12 SP5, SLES 12 SP5, SLE Workstation Extension 12 SP5 +1 more 6.8.8.1-71.165.1
  • ImageMagick SLE Module for Development Tools 15 SP2, SLE Module for Desktop Applications 15 SP2 7.0.7.34-10.15.1
  • ImageMagick SLES for SAP 15 SP1, SLES 15 SP1-LTSS, SLE High Performance Computing 15 SP1-LTSS 7.0.7.34-150000.3.123.1

suse advisories SUSE-SU-2023:4634-1SUSE-SU-2021:1277-1SUSE-SU-2021:1276-1

  • ImageMagick openSUSE Leap 15.2 7.0.7.34-lp152.12.15.1

opensuse advisories openSUSE-SU-2021:0606-1

  • imagemagick Alpine 3.13 7.0.11.13-r0
  • imagemagick Alpine 3.24, Alpine 3.23, Alpine 3.22 +8 more 7.0.11.1-r0
  • imagemagick6 Alpine 3.16 6.9.12.31-r0

alpine advisories ALPINE-CVE-2021-20309

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-20309 updated cvss 5.3

ImagemMagick: Division by zero in WaveImage() of MagickCore/visual-effects.c

  • Red Hat Enterprise Linux 6 ImageMagick, ImageMagick-c++, ImageMagick-perl Red Hat Enterprise Linux 7 ImageMagick, ImageMagick-c++, ImageMagick-perl
    affected: no fix planned “Out of support scope”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

2.31% chance of exploitation in the next 30 days, higher than 83% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 7.8 AV:N/AC:L/Au:N/C:N/I:N/A:C
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
julia ImageMagick_jll
<6.9.12+0
6.9.12+0

Affected products

  • n/a ImagemMagick

Classification

Weakness

References

Sources

Fencer Vulns 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.