CVE-2018-17456: Git before 2.14.5, 2.15.x before 2.15.3, 2.16.x before 2.16.5, 2.17.x before 2.17.2, 2.18.x before 2.18.1, and

This week

CRITICAL 9.8REMOTEWATCHLISTUPGRADEDOWNGRADEMITIGATE

CVE-2018-17456 is a critical-severity flaw (CVSS 9.8) affecting git, ansible tower, enterprise linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Git before 2.14.5, 2.15.x before 2.15.3, 2.16.x before 2.16.5, 2.17.x before 2.17.2, 2.18.x before 2.18.1, and 2.19.x before 2.19.1 allows remote code execution during processing of a recursive "git clone" of a superproject if a .gitmodules file has a URL field beginning with a '-' character.

Why this priority

Critical severity
EPSS top 1%: very likely to be exploited
Public exploit reference
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	97.4% (top 1%)
CISA exploited list	No
Weakness	CWE-88
Published	2018-10-06
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: git-scm · redhat

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

Am I affected?

Timeline

2018-10-06 14:29 UTCPublished CVE record published
2026-06-17 01:45 UTCUpdated Record last modified

git-scm git UPGRADE

Affected: >= 2.14.0 and < 2.14.5 · >= 2.15.0 and < 2.15.3 · >= 2.16.0 and < 2.16.5 · >= 2.17.0 and < 2.17.2 · >= 2.18.0 and < 2.18.1 · >= 2.19.0 and < 2.19.1

Fixed in: 2.14.5, 2.15.3, 2.16.5, 2.17.2, 2.18.1, 2.19.1

Safe to downgrade to: a release before 2.14.0

1. Check installed version

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

2. UPGRADE to 2.14.5 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade git

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 2.14.0 (Debian / Ubuntu)

apt-cache madison git sudo apt install git=<VERSION_BEFORE_2.14.0> sudo apt-mark hold git

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

dnf --showduplicates list git sudo dnf downgrade git-<VERSION_BEFORE_2.14.0> sudo dnf versionlock add git

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.

redhat ansible tower DOWNGRADE

Affected: 3.3

Fixed in: no fixed release known

Safe to downgrade to: a release before 3.3

1. Check installed version

apt-cache policy ansible-tower || rpm -q ansible-tower || ansible-tower --version

2. No fixed release: DOWNGRADE to a release before 3.3 (Debian / Ubuntu)

apt-cache madison ansible-tower sudo apt install ansible-tower=<VERSION_BEFORE_3.3> sudo apt-mark hold ansible-tower

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

dnf --showduplicates list ansible-tower sudo dnf downgrade ansible-tower-<VERSION_BEFORE_3.3> sudo dnf versionlock add ansible-tower

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.

redhat enterprise linux MITIGATE

Affected: 6.0 · 6.7 · 7.0 · 7.3 · 7.4 · 7.5 · 7.6

Fixed in: no fixed release known

Safe to downgrade to: a release before 6.0

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.

redhat enterprise linux desktop MITIGATE

Affected: 7.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 7.0

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.

redhat enterprise linux server MITIGATE

Affected: 7.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 7.0

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.

redhat enterprise linux server aus MITIGATE

Affected: 7.6

Fixed in: no fixed release known

Safe to downgrade to: a release before 7.6

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.

Exact fixes by distribution

A distro patch exists: prefer upgrading over downgrading.

Fedora 46 · copyparty · FIXED · 1.20.26-1.fc46 · FEDORA-2026-8fbe18458e · source

sudo dnf upgrade --advisory=FEDORA-2026-8fbe18458e

Fedora ELN · man-pages · FIXED · 6.20-1.eln159 · FEDORA-2026-f1f5fb11b4 · source

sudo dnf upgrade --advisory=FEDORA-2026-f1f5fb11b4

Debian 12 · git · FIXED · 1:2.19.1-1

sudo apt update && sudo apt install --only-upgrade git dpkg --compare-versions "$(dpkg-query -W -f='${Version}' git)" ge "1:2.19.1-1" && echo PATCHED || echo STILL-VULNERABLE

Debian 13 · git · FIXED · 1:2.19.1-1

sudo apt update && sudo apt install --only-upgrade git dpkg --compare-versions "$(dpkg-query -W -f='${Version}' git)" ge "1:2.19.1-1" && echo PATCHED || echo STILL-VULNERABLE

RHEL 6 · git · FIXED · git-1.7.1-10.el6_10

sudo dnf upgrade --advisory=RHSA-2020:0316 rpm -q git

RHEL 7 · git · FIXED · git-1.8.3.1-20.el7

sudo dnf upgrade --advisory=RHSA-2018:3408 rpm -q git

RHEL 8 · git · NOT AFFECTED

Alpine 3.20 · git · FIXED · git-2.19.1-r0

apk add --upgrade git apk info -v git

Alpine 3.21 · git · FIXED · git-2.19.1-r0

apk add --upgrade git apk info -v git

Alpine 3.22 · git · FIXED · git-2.19.1-r0

apk add --upgrade git apk info -v git

Alpine 3.23 · git · FIXED · git-2.19.1-r0

apk add --upgrade git apk info -v git

Amazon Linux 2 · see advisory · FIXED · ALAS2-2018-1093 · source

sudo yum update --advisory=ALAS2-2018-1093

Amazon Linux 1 · see advisory · FIXED · ALAS-2018-1093 · source

sudo yum update --advisory=ALAS-2018-1093

Public exploits and detection

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

GitHub PoC: AnonymKing/CVE-2018-17456 (5 stars)
GitHub PoC: shpik-kr/CVE-2018-17456 (0 stars)
GitHub PoC: matlink/CVE-2018-17456 (0 stars)
Write-up: www.exploit-db.com/exploits/45548/
Write-up: www.exploit-db.com/exploits/45631/
Exploit-DB: Git Submodule - Arbitrary Code Execution
Exploit-DB: Git Submodule - Arbitrary Code Execution (PoC)
Metasploit: Malicious Git HTTP Server For CVE-2018-17456

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-2018-17456?

git: upgrade to 2.14.5, 2.15.3, 2.16.5, 2.17.2, 2.18.1, 2.19.1; ansible tower: downgrade or apply the listed mitigation; enterprise linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2018-17456 being exploited?

CVE-2018-17456 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-2018-17456 affect?

CVE-2018-17456 affects git, ansible tower, enterprise linux. Severity is critical (CVSS 9.8). Git before 2.14.5, 2.15.x before 2.15.3, 2.16.x before 2.16.5, 2.17.x before 2.17.2, 2.18.x before 2.18.1, and 2.19.x before 2.19.1 allows remote code execution during processing of a recursive "git clone" of a superproject if a .gitmodules

How urgent is CVE-2018-17456?

Priority 74/100. Critical severity; EPSS top 1%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Ansible vulnerabilities · Git vulnerabilities

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References

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