CVE-2020-36773: ghostscript Use-After-Free — Fix

Description

Artifex Ghostscript before 9.53.0 has an out-of-bounds write and use-after-free in devices/vector/gdevtxtw.c (for txtwrite) because a single character code in a PDF document can map to more than one Unicode code point (e.g., for a ligature).

Is your site exposed to CVE-2020-36773?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

9.8

CRITICAL

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

Weakness Type (CWE)

CWE-416 Use After Free

CWE-787 Out-of-bounds Write

Affected Products

Vendor	Product	Versions
artifex	ghostscript	All
artifex	ghostscript	All
artifex	ghostscript	All
artifex	ghostscript	All
artifex	ghostscript	All

References

Advisories & Patches

https://bugs.ghostscript.com/show_bug.cgi?id=702229 https://bugs.ghostscript.com/show_bug.cgi?id=702229

Other References

https://bugzilla.opensuse.org/show_bug.cgi?id=1177922 https://git.ghostscript.com/?p=ghostpdl.git%3Ba=commit%3Bh=8c7bd787defa071c96289b7da9397f673fddb874 https://github.com/ArtifexSoftware/ghostpdl-downloads/releases/tag/gs9530 https://bugzilla.opensuse.org/show_bug.cgi?id=1177922 https://git.ghostscript.com/?p=ghostpdl.git%3Ba=commit%3Bh=8c7bd787defa071c96289b7da9397f673fddb874 https://github.com/ArtifexSoftware/ghostpdl-downloads/releases/tag/gs9530

Frequently Asked Questions

What is CVE-2020-36773? +

Artifex Ghostscript before 9.53.0 has an out-of-bounds write and use-after-free in devices/vector/gdevtxtw.c (for txtwrite) because a single character code in a PDF document can map to more than one Unicode code point (e.g., for a ligature). It has a CVSS v3.1 base score of 9.8 (CRITICAL).

How severe is CVE-2020-36773? +

CVE-2020-36773 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately.

What products are affected by CVE-2020-36773? +

CVE-2020-36773 affects products from artifex, specifically: ghostscript. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2020-36773? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-6040

A heap use-after-free existed when importing the blank-width characters of an ODF number format. A position value read from the …

CVE-2025-24898

rust-openssl is a set of OpenSSL bindings for the Rust programming language. In affected versions `ssl::select_next_proto` can return a slice …

CVE-2025-31115

XZ Utils provide a general-purpose data-compression library plus command-line tools. In XZ Utils 5.3.3alpha to 5.8.0, the multithreaded .xz decoder …

CVE-2025-31498

c-ares is an asynchronous resolver library. From 1.32.3 through 1.34.4, there is a use-after-free in read_answers() when process_answer() may re-enqueue …

CVE-2025-4516

There is an issue in CPython when using `bytes.decode("unicode_escape", error="ignore|replace")`. If you are not using the "unicode_escape" encoding or an …

CVE-2025-5991

There is a "Use After Free" vulnerability in Qt's QHttp2ProtocolHandler in the QtNetwork module. This only affects HTTP/2 handling, HTTP …

CVE-2020-36773