CVE-2018-11489: The DGifDecompressLine function in dgif_lib.c in GIFLIB (possibly version 3.0.x), as later shipped in cgif.c i

This month

HIGH 8.8UPGRADEDOWNGRADE

CVE-2018-11489 is a high-severity flaw (CVSS 8.8) affecting giflib, sam2p. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The DGifDecompressLine function in dgif_lib.c in GIFLIB (possibly version 3.0.x), as later shipped in cgif.c in sam2p 0.49.4, has a heap-based buffer overflow because a certain CrntCode array index is not checked. This will lead to a denial of service or possibly unspecified other impact.

Why this priority

High severity
Public exploit reference

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	2.5% (top 16%)
CISA exploited list	No
Weakness	CWE-129, CWE-787
Published	2018-05-26
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: giflib project · sam2p project

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

Am I affected?

Timeline

2018-05-26 18:29 UTCPublished CVE record published
2026-06-17 01:36 UTCUpdated Record last modified

giflib project giflib UPGRADE

Affected: >= 3.0 and <= 3.1.1

Fixed in: newer than 3.1.1

Safe to downgrade to: a release before 3.0

1. Check installed version

apt-cache policy giflib || rpm -q giflib || giflib --version

2. UPGRADE to newer than 3.1.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade giflib

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade giflib

Note

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

3. If no update is available yet, DOWNGRADE to a release before 3.0 (Debian / Ubuntu)

apt-cache madison giflib sudo apt install giflib=<VERSION_BEFORE_3.0> sudo apt-mark hold giflib

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list giflib sudo dnf downgrade giflib-<VERSION_BEFORE_3.0> sudo dnf versionlock add giflib

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

sam2p project sam2p DOWNGRADE

Affected: 0.49.4

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.49.4

1. Check installed version

apt-cache policy sam2p || rpm -q sam2p || sam2p --version

2. No fixed release: DOWNGRADE to a release before 0.49.4 (Debian / Ubuntu)

apt-cache madison sam2p sudo apt install sam2p=<VERSION_BEFORE_0.49.4> sudo apt-mark hold sam2p

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list sam2p sudo dnf downgrade sam2p-<VERSION_BEFORE_0.49.4> sudo dnf versionlock add sam2p

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

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-2018-11489?

giflib: upgrade to newer than 3.1.1; sam2p: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2018-11489 being exploited?

CVE-2018-11489 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-2018-11489 affect?

CVE-2018-11489 affects giflib, sam2p. Severity is high (CVSS 8.8). The DGifDecompressLine function in dgif_lib.c in GIFLIB (possibly version 3.0.x), as later shipped in cgif.c in sam2p 0.49.4, has a heap-based buffer overflow because a certain CrntCode array index is not checked. This will lead to a denial

How urgent is CVE-2018-11489?

Priority 57/100. High severity; Public exploit reference

Related CVEs

CVE-2023-48161 HIGH 7.1 DOWNGRADE Buffer Overflow vulnerability in GifLib Project GifLib v.5.2.1 allows a local attacker to obtain sensitive inf
CVE-2026-26740 HIGH 8.2 DOWNGRADE Buffer Overflow vulnerability in giflib v.5.2.2 allows a remote attacker to cause a denial of service via the
CVE-2026-23868 MEDIUM 5.1 UPGRADE Giflib contains a double-free vulnerability that is the result of a shallow copy in GifMakeSavedImage and inco
CVE-2024-45993 MEDIUM 6.5 DOWNGRADE Giflib Project v5.2.2 is vulnerable to a heap buffer overflow via gif2rgb.
CVE-2023-39742 MEDIUM 5.5 DOWNGRADE giflib v5.2.1 was discovered to contain a segmentation fault via the component getarg.c.

References

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