CVE-2021-20240: A flaw was found in gdk-pixbuf in versions before 2.42.0

Q: How do I fix CVE-2021-20240?

gdk-pixbuf: upgrade to 2.39.2; fedora: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2021-20240 being exploited?

CVE-2021-20240 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2021-20240 affect?

CVE-2021-20240 affects gdk-pixbuf, fedora. Severity is high (CVSS 8.8). A flaw was found in gdk-pixbuf in versions before 2.42.0. An integer wraparound leading to an out of bounds write can occur when a crafted GIF image is loaded. An attacker may cause applications to crash or could potentially execute code on

This month

HIGH 8.8UPGRADEMITIGATE

CVE-2021-20240 is a high-severity flaw (CVSS 8.8) affecting gdk-pixbuf, fedora. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A flaw was found in gdk-pixbuf in versions before 2.42.0. An integer wraparound leading to an out of bounds write can occur when a crafted GIF image is loaded. An attacker may cause applications to crash or could potentially execute code on the victim system. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

Why this priority

High severity

A fixed release or distro patch exists.

Risk facts

CVSS score	8.8 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	2.3% (top 16%)
CISA exploited list	No
Weakness	CWE-191
Published	2021-05-28
Last modified	2026-06-17

Publisher (CNA): Red Hat, Inc. · Vendor: fedoraproject · gnome

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2021-05-28 11:15 UTCPublished CVE record published
2026-06-17 03:33 UTCUpdated Record last modified

gnome gdk-pixbuf UPGRADE

Affected: < 2.39.2

Fixed in: 2.39.2

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy gdk-pixbuf || rpm -q gdk-pixbuf || gdk-pixbuf --version

2. UPGRADE to 2.39.2 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade gdk-pixbuf

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade gdk-pixbuf

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

fedoraproject fedora MITIGATE

Affected: 33 · 34

Fixed in: no fixed release known

Safe to downgrade to: a release before 33

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-20240?

gdk-pixbuf: upgrade to 2.39.2; fedora: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-20240 being exploited?

CVE-2021-20240 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-20240 affect?

CVE-2021-20240 affects gdk-pixbuf, fedora. Severity is high (CVSS 8.8). A flaw was found in gdk-pixbuf in versions before 2.42.0. An integer wraparound leading to an out of bounds write can occur when a crafted GIF image is loaded. An attacker may cause applications to crash or could potentially execute code on

How urgent is CVE-2021-20240?

Priority 52/100. High severity

Related CVEs

CVE-2026-5201 HIGH 7.5 UPGRADE UPGRADE A flaw was found in the gdk-pixbuf library
CVE-2021-46829 HIGH 7.8 UPGRADE MITIGATE GNOME GdkPixbuf (aka GDK-PixBuf) before 2.42.8 allows a heap-based buffer overflow when compositing or clearin
CVE-2020-29385 MEDIUM 5.5 UPGRADE MITIGATE GNOME gdk-pixbuf (aka GdkPixbuf) before 2.42.2 allows a denial of service (infinite loop) in lzw.c in the func
CVE-2017-6314 MEDIUM 5.5 UPGRADE MITIGATE The make_available_at_least function in io-tiff.c in gdk-pixbuf allows context-dependent attackers to cause a
CVE-2017-6313 HIGH 7.1 UPGRADE MITIGATE Integer underflow in the load_resources function in io-icns.c in gdk-pixbuf allows context-dependent attackers

References

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