Which products and versions are affected by CVE-2021-3407?

Affected: Mupdf (Artifex) versions 1.18.0, >= mupdf 1.18.0; Debian Linux versions 9.0; Fedora (Fedoraproject) versions 32, 33, 34, among others. The full list is in the CVE brief.

Is CVE-2021-3407 being exploited in the wild?

It is not listed in any known-exploited vulnerabilities catalog.

Is CVE-2021-3407 in the CISA KEV catalog?

No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.

Is there a public exploit for CVE-2021-3407?

Public exploit code is available.

Is there a fix for CVE-2021-3407?

Fixed versions are available, including libmupdf-dev 1.12.0+ds1-1ubuntu0.1~esm1, libmupdf-dev 1.16.1+ds1-1ubuntu1+esm1, libmupdf-dev 1.7a-1ubuntu0.1~esm1.

How urgently should CVE-2021-3407 be patched?

Brandefense priority: patch immediately, because it is very likely to be exploited soon.

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Vulnerability Intelligence

CVE-2021-3407

HighPublic exploit

Double free of object during linearization may lead to memory corruption and other potential consequences.

Published Feb 23, 2021 · Updated Aug 7, 2026 · Also known as DEBIAN-CVE-2021-3407, UBUNTU-CVE-2021-3407

Key Facts

Patch immediately

CVE-2021-3407 is a high-severity vulnerability (CVSS 7.8 v3.1) affecting Mupdf (Artifex), Debian Linux, Fedora (Fedoraproject) and 3 more products.
It is not listed in any known-exploited vulnerabilities catalog. Public exploit code is available.
EPSS estimates a 50% probability of exploitation in the next 30 days.
Fixed versions are available, including libmupdf-dev 1.12.0+ds1-1ubuntu0.1~esm1, libmupdf-dev 1.16.1+ds1-1ubuntu1+esm1, libmupdf-dev 1.7a-1ubuntu0.1~esm1.
Brandefense priority: patch immediately, because it is very likely to be exploited soon.

CVSS v3.1

7.8

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS (30-day exploit likelihood)

50%

Higher than 98.8% of all scored CVEs

Exploited in the wild

No known

Not in a known-exploited catalog

Public exploit code

Available

Proof-of-concept or weaponized module

Get the full CVE-2021-3407 brief as a PDF

Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.

Description

A flaw was found in mupdf 1.18.0. Double free of object during linearization may lead to memory corruption and other potential consequences.

Affected Products

44 affected entries in total

Product	Affected versions	Fixed in
MupdfArtifex	1.18.0, >= mupdf 1.18.0	1.18.0-2
Debian LinuxDebian	9.0	n/a
FedoraFedoraproject	32, 33, 34	n/a
zathura-pdf-mupdfarch	See advisory	0.3.6-5
libmupdf-devubuntu	See advisory	1.12.0+ds1-1ubuntu0.1~esm1

1 more affected products in the full CVE brief

Patched Releases

libmupdf-dev

1.12.0+ds1-1ubuntu0.1~esm1, 1.16.1+ds1-1ubuntu1+esm1, 1.7a-1ubuntu0.1~esm1

Mupdf

1.12.0+ds1-1ubuntu0.1~esm1, 1.16.1+ds1-1ubuntu1+esm1, 1.17.0+ds1-1.3, 1.18.0-2, 1.18.0-r1, 1.7a-1ubuntu0.1~esm1, 1.9a+ds1-4+deb9u6

mupdf-tools

1.12.0+ds1-1ubuntu0.1~esm1, 1.16.1+ds1-1ubuntu1+esm1, 1.7a-1ubuntu0.1~esm1

zathura-pdf-mupdf

0.3.6-5

Timeline

Publicly disclosed
Feb 23, 2021
Last updated
Aug 7, 2026

Weakness Type

CWE-415 Double Free

References

7 more references in the full CVE brief

FAQ

Common Questions.

A flaw was found in mupdf 1.18.0.
Affected: Mupdf (Artifex) versions 1.18.0, >= mupdf 1.18.0; Debian Linux versions 9.0; Fedora (Fedoraproject) versions 32, 33, 34, among others. The full list is in the CVE brief.
It is not listed in any known-exploited vulnerabilities catalog.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
Public exploit code is available.
Fixed versions are available, including libmupdf-dev 1.12.0+ds1-1ubuntu0.1~esm1, libmupdf-dev 1.16.1+ds1-1ubuntu1+esm1, libmupdf-dev 1.7a-1ubuntu0.1~esm1.
Brandefense priority: patch immediately, because it is very likely to be exploited soon.

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