CVE-2026-37458: Missing input validation in the MP_REACH_NLRI component of FRRouting (FRR) stable/10.0 to stable/10.6 allows a

Routine

MEDIUM 6.5UPGRADE

CVE-2026-37458 is a medium-severity flaw (CVSS 6.5) affecting frrouting. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Missing input validation in the MP_REACH_NLRI component of FRRouting (FRR) stable/10.0 to stable/10.6 allows authenticated attackers to cause a Denial of Service (DoS) via supplying a crafted UPDATE message.

Why this priority

No elevated risk signals yet

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	0.2% (top 84%)
CISA exploited list	No
Weakness	CWE-20
Published	2026-05-04
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: frrouting

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

Am I affected?

Timeline

2026-05-04 16:16 UTCPublished CVE record published
2026-06-17 10:41 UTCUpdated Record last modified

frrouting frrouting UPGRADE

Affected: >= 10.0 and <= 10.6.0

Fixed in: newer than 10.6.0

Safe to downgrade to: a release before 10.0

1. Check installed version

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

2. UPGRADE to newer than 10.6.0 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade frrouting

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 10.0 (Debian / Ubuntu)

apt-cache madison frrouting sudo apt install frrouting=<VERSION_BEFORE_10.0> sudo apt-mark hold frrouting

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

dnf --showduplicates list frrouting sudo dnf downgrade frrouting-<VERSION_BEFORE_10.0> sudo dnf versionlock add frrouting

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.

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-2026-37458?

frrouting: upgrade to newer than 10.6.0. Exact commands for each OS are on this page.

Is CVE-2026-37458 being exploited?

CVE-2026-37458 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-2026-37458 affect?

CVE-2026-37458 affects frrouting. Severity is medium (CVSS 6.5). Missing input validation in the MP_REACH_NLRI component of FRRouting (FRR) stable/10.0 to stable/10.6 allows authenticated attackers to cause a Denial of Service (DoS) via supplying a crafted UPDATE message.

How urgent is CVE-2026-37458?

Priority 27/100. No elevated risk signals yet.

Related CVEs

CVE-2026-28532 MEDIUM 6.5 UPGRADE FRRouting before 10.5.3 contains an integer overflow vulnerability in seven OSPF Traffic Engineering and Segme
CVE-2026-37457 HIGH 7.5 DOWNGRADE An off-by-one out-of-bounds write vulnerability in the bgp_flowspec_op_decode() function (bgpd/bgp_flowspec_ut

References

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