CVE-2019-6977: gdImageColorMatch in gd_color_match.c in the GD Graphics Library (aka LibGD) 2.2.5, as used in the imagecolorm

This week

HIGH 8.8WATCHLISTDOWNGRADEUPGRADEMITIGATE

CVE-2019-6977 is a high-severity flaw (CVSS 8.8) affecting libgd, php, debian linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

gdImageColorMatch in gd_color_match.c in the GD Graphics Library (aka LibGD) 2.2.5, as used in the imagecolormatch function in PHP before 5.6.40, 7.x before 7.1.26, 7.2.x before 7.2.14, and 7.3.x before 7.3.1, has a heap-based buffer overflow. This can be exploited by an attacker who is able to trigger imagecolormatch calls with crafted image data.

Why this priority

High severity
EPSS top 1%: very likely to be exploited
Public exploit reference
On your watchlist

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	71.5% (top 1%)
CISA exploited list	No
Weakness	CWE-787
Published	2019-01-27
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: canonical · debian · libgd · netapp · php

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

Am I affected?

Timeline

2019-01-27 02:29 UTCPublished CVE record published
2026-06-17 02:39 UTCUpdated Record last modified

libgd libgd DOWNGRADE

Affected: 2.2.5

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.2.5

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 2.2.5 (Debian / Ubuntu)

apt-cache madison libgd sudo apt install libgd=<VERSION_BEFORE_2.2.5> sudo apt-mark hold libgd

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

dnf --showduplicates list libgd sudo dnf downgrade libgd-<VERSION_BEFORE_2.2.5> sudo dnf versionlock add libgd

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.

php php UPGRADE

Affected: < 5.6.40 · >= 7.0.0 and < 7.1.26 · >= 7.2.0 and < 7.2.14 · 7.3.0

Fixed in: 5.6.40, 7.1.26, 7.2.14

Safe to downgrade to: a release before 7.0.0

1. Check installed version

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

2. UPGRADE to 5.6.40 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade php

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 7.0.0 (Debian / Ubuntu)

apt-cache madison php sudo apt install php=<VERSION_BEFORE_7.0.0> sudo apt-mark hold php

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

dnf --showduplicates list php sudo dnf downgrade php-<VERSION_BEFORE_7.0.0> sudo dnf versionlock add php

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.

debian debian linux MITIGATE

Affected: 8.0 · 9.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 8.0

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.

canonical ubuntu linux MITIGATE

Affected: 14.04 · 16.04 · 18.04 · 18.10

Fixed in: no fixed release known

Safe to downgrade to: a release before 14.04

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.

netapp storage automation store MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy storage-automation-store || rpm -q storage-automation-store || storage-automation-store --version

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Exploit-DB: PHP 7.2 - 'imagecolormatch()' Out of Band Heap Write

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-2019-6977?

libgd: downgrade or apply the listed mitigation; php: upgrade to 5.6.40, 7.1.26, 7.2.14; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2019-6977 being exploited?

CVE-2019-6977 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-2019-6977 affect?

CVE-2019-6977 affects libgd, php, debian linux. Severity is high (CVSS 8.8). gdImageColorMatch in gd_color_match.c in the GD Graphics Library (aka LibGD) 2.2.5, as used in the imagecolormatch function in PHP before 5.6.40, 7.x before 7.1.26, 7.2.x before 7.2.14, and 7.3.x before 7.3.1, has a heap-based buffer overfl

How urgent is CVE-2019-6977?

Priority 66/100. High severity; EPSS top 1%: very likely to be exploited; Public exploit reference; On your watchlist

Software pages

PHP vulnerabilities · Ubuntu vulnerabilities · Debian vulnerabilities

Related CVEs

CVE-2021-40812 MEDIUM 6.5 UPGRADE The GD Graphics Library (aka LibGD) through 2.3.2 has an out-of-bounds read because of the lack of certain gdG
CVE-2021-40145 HIGH 7.5 UPGRADE gdImageGd2Ptr in gd_gd2.c in the GD Graphics Library (aka LibGD) through 2.3.2 has a double free
CVE-2021-38115 MEDIUM 6.5 UPGRADE read_header_tga in gd_tga.c in the GD Graphics Library (aka LibGD) through 2.3.2 allows remote attackers to ca
CVE-2019-6978 CRITICAL 9.8 DOWNGRADE MITIGATE The GD Graphics Library (aka LibGD) 2.2.5 has a double free in the gdImage*Ptr() functions in gd_gif_out.c, gd
CVE-2019-11038 MEDIUM 5.3 DOWNGRADE UPGRADE When using the gdImageCreateFromXbm() function in the GD Graphics Library (aka LibGD) 2.2.5, as used in the PH

References

← Back to latest CVEs