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Fencer Vulns
high 8.8

CVE-2021-40633 json

A memory leak (out-of-memory) in gif2rgb in util/gif2rgb.c in giflib 5.1.4 allows remote attackers trigger an out of memory exception or de…

published 2022-06-14 4 y ago modified 2026-07-30 3 mo ago also EUVD-2021-27807 , JLSEC-2026-816

cvss
8.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.7%
EPSS 1.7% chance of exploitation in 30 days, percentile 77%
public exploits
0
none known

Summary

A memory leak (out-of-memory) in gif2rgb in util/gif2rgb.c in giflib 5.1.4 allows remote attackers trigger an out of memory exception or denial of service via a gif format file.

Patch / fix

  • julia Giflib_jll 5.2.1+0
  • giflib Debian 14, Debian 13 5.2.2-1

debian advisories DEBIAN-CVE-2021-40633

  • giflib Ubuntu 20.04 LTS 5.1.9-1ubuntu0.1
  • giflib Ubuntu 22.04 LTS 5.1.9-2ubuntu0.1
  • giflib Ubuntu Pro 16.04 LTS 5.1.4-0.3~16.04.1+esm1
  • giflib Ubuntu Pro 18.04 LTS 5.1.4-2ubuntu0.1+esm1

ubuntu advisories UBUNTU-CVE-2021-40633

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

  • giflib SLES for SAP 12 SP5, SLES 12 SP5, SLE Software Development Kit 12 SP5 5.0.5-13.3.1
  • giflib SLES for SAP 15 SP4, SLES for SAP 15 SP3, SLES for SAP 15 SP2 +12 more 5.2.2-150000.4.13.1

suse advisories SUSE-SU-2024:1622-1SUSE-SU-2024:0786-1

  • giflib openSUSE Tumbleweed 5.2.2-1.1

opensuse advisories openSUSE-SU-2024:13723-1

  • giflib Alpine 3.24, Alpine 3.23, Alpine 3.22 +5 more 5.2.2-r0

alpine advisories ALPINE-CVE-2021-40633

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

  • giflib Azure Linux 3.0 5.2.1-10

azure linux advisories AZL-41515

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

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-2021-40633 updated

  • Red Hat All currently supported Red Hat products
    not affected: component not present

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

1.72% chance of exploitation in the next 30 days, higher than 77% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • sourceforge.net https://sourceforge.net/p/giflib/bugs/157/ referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
NVD 2.0 5.1 AV:N/AC:H/Au:N/C:P/I:P/A:P
OSV 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
julia Giflib_jll
<5.2.1+0
5.2.1+0

Classification

Weakness
  • CWE-401 Missing Release of Memory after Effective Lifetime

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.