CVE-2019-18183: pacman before 5.2 is vulnerable to arbitrary command injection in lib/libalpm/sync.c in the apply_deltas() fun

Q: How do I fix CVE-2019-18183?

pacman: upgrade to 5.2; fedora: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2019-18183 being exploited?

CVE-2019-18183 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-2019-18183 affect?

CVE-2019-18183 affects pacman, fedora. Severity is critical (CVSS 9.8). pacman before 5.2 is vulnerable to arbitrary command injection in lib/libalpm/sync.c in the apply_deltas() function. This can be exploited when unsigned databases are used. To exploit the vulnerability, the user must enable the non-default

Q: How urgent is CVE-2019-18183?

Priority 67/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

This week

CRITICAL 9.8REMOTEUPGRADEMITIGATE

CVE-2019-18183 is a critical-severity flaw (CVSS 9.8) affecting pacman, fedora. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

pacman before 5.2 is vulnerable to arbitrary command injection in lib/libalpm/sync.c in the apply_deltas() function. This can be exploited when unsigned databases are used. To exploit the vulnerability, the user must enable the non-default delta feature and retrieve an attacker-controlled crafted database and delta file.

Why this priority

Critical severity
Public exploit reference
Remotely exploitable, no login, no user action

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	3.7% (top 10%)
CISA exploited list	No
Weakness	CWE-78
Published	2020-02-24
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: fedoraproject · pacman project

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

Am I affected?

Timeline

2020-02-24 15:15 UTCPublished CVE record published
2026-06-17 02:24 UTCUpdated Record last modified

pacman project pacman UPGRADE

Affected: < 5.2

Fixed in: 5.2

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to 5.2 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade pacman

Note

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

fedoraproject fedora MITIGATE

Affected: 30 · 31 · 32

Fixed in: no fixed release known

Safe to downgrade to: a release before 30

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-2019-18183?

pacman: upgrade to 5.2; fedora: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2019-18183 being exploited?

CVE-2019-18183 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-2019-18183 affect?

CVE-2019-18183 affects pacman, fedora. Severity is critical (CVSS 9.8). pacman before 5.2 is vulnerable to arbitrary command injection in lib/libalpm/sync.c in the apply_deltas() function. This can be exploited when unsigned databases are used. To exploit the vulnerability, the user must enable the non-default

How urgent is CVE-2019-18183?

Priority 67/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

Related CVEs

CVE-2019-18182 CRITICAL 9.8 UPGRADE MITIGATE pacman before 5.2 is vulnerable to arbitrary command injection in conf.c in the download_with_xfercommand() fu

References

← Back to latest CVEs