CVE-2018-1000140: rsyslog librelp version 1.2.14 and earlier contains a Buffer Overflow vulnerability in the checking of x509 ce

Q: How do I fix CVE-2018-1000140?

librelp: upgrade to newer than 1.2.14; debian linux: mitigate or apply the listed mitigation; ubuntu linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2018-1000140 being exploited?

CVE-2018-1000140 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-2018-1000140 affect?

CVE-2018-1000140 affects librelp, debian linux, ubuntu linux. Severity is critical (CVSS 9.8). rsyslog librelp version 1.2.14 and earlier contains a Buffer Overflow vulnerability in the checking of x509 certificates from a peer that can result in Remote code execution. This attack appear to be exploitable a remote attacker that can c

Q: How urgent is CVE-2018-1000140?

Priority 73/100. Critical severity; EPSS top 5%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action; On your watchlist

This week

CRITICAL 9.8REMOTEWATCHLISTUPGRADEMITIGATEMITIGATE

CVE-2018-1000140 is a critical-severity flaw (CVSS 9.8) affecting librelp, debian linux, ubuntu linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

rsyslog librelp version 1.2.14 and earlier contains a Buffer Overflow vulnerability in the checking of x509 certificates from a peer that can result in Remote code execution. This attack appear to be exploitable a remote attacker that can connect to rsyslog and trigger a stack buffer overflow by sending a specially crafted x509 certificate.

Why this priority

Critical severity
EPSS top 5%: 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	9.3% (top 5%)
CISA exploited list	No
Weakness	CWE-787
Published	2018-03-23
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: canonical · debian · redhat · rsyslog

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

Am I affected?

Timeline

2018-03-23 21:29 UTCPublished CVE record published
2026-06-17 01:32 UTCUpdated Record last modified

rsyslog librelp UPGRADE

Affected: <= 1.2.14

Fixed in: newer than 1.2.14

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to newer than 1.2.14 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade librelp

Note

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

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

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.

redhat enterprise linux desktop MITIGATE

Affected: 6.0 · 7.0

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 server MITIGATE

Affected: 6.0 · 7.0

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 server aus MITIGATE

Affected: 6.6 · 7.2 · 7.3 · 7.4 · 7.6

Fixed in: no fixed release known

Safe to downgrade to: a release before 6.6

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 · shotcut · FIXED · 26.10.30-1.fc46 · FEDORA-2026-7787c7fc2d · source

sudo dnf upgrade --advisory=FEDORA-2026-7787c7fc2d

Ubuntu 20.04 · librelp · NOT AFFECTED

Ubuntu 22.04 · librelp · NOT AFFECTED

Debian 12 · librelp · FIXED · 1.2.15-1

sudo apt update && sudo apt install --only-upgrade librelp dpkg --compare-versions "$(dpkg-query -W -f='${Version}' librelp)" ge "1.2.15-1" && echo PATCHED || echo STILL-VULNERABLE

Debian 13 · librelp · FIXED · 1.2.15-1

sudo apt update && sudo apt install --only-upgrade librelp dpkg --compare-versions "$(dpkg-query -W -f='${Version}' librelp)" ge "1.2.15-1" && echo PATCHED || echo STILL-VULNERABLE

RHEL 6 · librelp · FIXED · librelp-1.2.7-3.el6_9.1

sudo dnf upgrade --advisory=RHSA-2018:1225 rpm -q librelp

RHEL 6.6 Advanced Update Support · librelp · FIXED · librelp-1.2.7-3.el6_6.1

sudo dnf upgrade --advisory=RHSA-2018:1701 rpm -q librelp

RHEL 6.6 Telco Extended Update Support · librelp · FIXED · librelp-1.2.7-3.el6_6.1

sudo dnf upgrade --advisory=RHSA-2018:1701 rpm -q librelp

RHEL 6.7 Extended Update Support · librelp · FIXED · librelp-1.2.7-3.el6_7.1

sudo dnf upgrade --advisory=RHSA-2018:1702 rpm -q librelp

RHEL 7 · librelp · FIXED · librelp-1.2.12-1.el7_5.1

sudo dnf upgrade --advisory=RHSA-2018:1223 rpm -q librelp

Amazon Linux 2 · see advisory · FIXED · ALAS2-2018-998 · source

sudo yum update --advisory=ALAS2-2018-998

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: s0/rsyslog-librelp-CVE-2018-1000140 (0 stars)
GitHub PoC: s0/rsyslog-librelp-CVE-2018-1000140-fixed (0 stars)
Write-up: github.com/rsyslog/librelp/blob/532aa362f0f7a8d037505b0a27a1df452f9bac9e/src/tcp.c#L1205

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-2018-1000140?

librelp: upgrade to newer than 1.2.14; debian linux: mitigate or apply the listed mitigation; ubuntu linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2018-1000140 being exploited?

CVE-2018-1000140 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-2018-1000140 affect?

CVE-2018-1000140 affects librelp, debian linux, ubuntu linux. Severity is critical (CVSS 9.8). rsyslog librelp version 1.2.14 and earlier contains a Buffer Overflow vulnerability in the checking of x509 certificates from a peer that can result in Remote code execution. This attack appear to be exploitable a remote attacker that can c

How urgent is CVE-2018-1000140?

Priority 73/100. Critical severity; EPSS top 5%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Ubuntu vulnerabilities · Debian vulnerabilities

References

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