CVE-2018-5381: The Quagga BGP daemon (bgpd) prior to version 1.2.3 has a bug in its parsing of "Capabilities" in BGP OPEN mes

Q: How do I fix CVE-2018-5381?

quagga: upgrade to newer than 1.2.2; ubuntu linux: mitigate or apply the listed mitigation; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2018-5381 being exploited?

CVE-2018-5381 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-2018-5381 affect?

CVE-2018-5381 affects quagga, ubuntu linux, debian linux. Severity is medium (CVSS 6.5). The Quagga BGP daemon (bgpd) prior to version 1.2.3 has a bug in its parsing of "Capabilities" in BGP OPEN messages, in the bgp_packet.c:bgp_capability_msg_parse function. The parser can enter an infinite loop on invalid capabilities if a M

Q: How urgent is CVE-2018-5381?

Priority 52/100. EPSS top 2%: very likely to be exploited; On your watchlist

This week

MEDIUM 6.5WATCHLISTUPGRADEMITIGATEMITIGATE

CVE-2018-5381 is a medium-severity flaw (CVSS 6.5) affecting quagga, ubuntu linux, debian linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The Quagga BGP daemon (bgpd) prior to version 1.2.3 has a bug in its parsing of "Capabilities" in BGP OPEN messages, in the bgp_packet.c:bgp_capability_msg_parse function. The parser can enter an infinite loop on invalid capabilities if a Multi-Protocol capability does not have a recognized AFI/SAFI, causing a denial of service.

Why this priority

EPSS top 2%: very likely to be exploited
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	30.2% (top 2%)
CISA exploited list	No
Weakness	CWE-228, CWE-835
Published	2018-02-19
Last modified	2026-06-17

Publisher (CNA): CERT/CC · Vendor: canonical · debian · quagga · siemens

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

Am I affected?

Timeline

2018-02-19 13:29 UTCPublished CVE record published
2026-06-17 02:00 UTCUpdated Record last modified

quagga quagga UPGRADE

Affected: <= 1.2.2

Fixed in: newer than 1.2.2

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to newer than 1.2.2 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade quagga

Note

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

canonical ubuntu linux MITIGATE

Affected: 14.04 · 16.04 · 17.10

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.

debian debian linux MITIGATE

Affected: 7.0 · 8.0 · 9.0

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.

siemens ruggedcom rox ii firmware UPGRADE

Affected: < 2.13.0

Fixed in: 2.13.0

Safe to downgrade to: no unaffected older release

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-2018-5381?

quagga: upgrade to newer than 1.2.2; ubuntu linux: mitigate or apply the listed mitigation; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2018-5381 being exploited?

CVE-2018-5381 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-2018-5381 affect?

CVE-2018-5381 affects quagga, ubuntu linux, debian linux. Severity is medium (CVSS 6.5). The Quagga BGP daemon (bgpd) prior to version 1.2.3 has a bug in its parsing of "Capabilities" in BGP OPEN messages, in the bgp_packet.c:bgp_capability_msg_parse function. The parser can enter an infinite loop on invalid capabilities if a M

How urgent is CVE-2018-5381?

Priority 52/100. EPSS top 2%: very likely to be exploited; On your watchlist

Software pages

Ubuntu vulnerabilities · Debian vulnerabilities · Siemens vulnerabilities

Related CVEs

CVE-2021-44038 HIGH 7.8 UPGRADE An issue was discovered in Quagga through 1.2.4
CVE-2018-5380 MEDIUM 4.3 UPGRADE MITIGATE The Quagga BGP daemon (bgpd) prior to version 1.2.3 can overrun internal BGP code-to-string conversion tables
CVE-2018-5379 HIGH 7.5 UPGRADE MITIGATE The Quagga BGP daemon (bgpd) prior to version 1.2.3 can double-free memory when processing certain forms of UP
CVE-2018-5378 HIGH 7.1 UPGRADE MITIGATE The Quagga BGP daemon (bgpd) prior to version 1.2.3 does not properly bounds check the data sent with a NOTIFY
CVE-2017-5495 HIGH 7.5 UPGRADE All versions of Quagga, 0.93 through 1.1.0, are vulnerable to an unbounded memory allocation in the telnet 'vt

References

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