Use-after-free in MuPDF - CVE-2020-21896
Published: October 17, 2025
Vulnerability identifier: #VU117353
CSH Severity: High
CVSS v4: 9.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2020-21896
CWE-ID: CWE-416
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to compromise vulnerable system.
The vulnerability exists due to a use-after-free error within the svg_dev_text_span_as_paths_defs() function in source/fitz/svg-device.c when handling PDF files. A remote attacker can pass specially crafted input to the application and compromise the affected system.
Successful exploitation of the vulnerability may allow an attacker to compromise vulnerable system.
Affected software
MuPDF
Ubuntu
mupdf (Ubuntu package)
Ubuntu
mupdf (Ubuntu package)
How to mitigate CVE-2020-21896
Install updates from vendor's website.
mupdf (Ubuntu package) - addressed in versions 1.7a-1ubuntu0.1~esm1, 1.12.0+ds1-1ubuntu0.1~esm1, 1.16.1+ds1-1ubuntu1+esm1