What is CVE-2023-38406?

CVE-2023-38406 is a critical-severity vulnerability in Frrouting, classified under Improper Handling of Exceptional Conditions. CVSS score: 9.8/10. Published 2023-11-06.

How severe is CVE-2023-38406?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Vulnerability in Frrouting

CVE-2023-38406

bgpd/bgp_flowspec.c in FRRouting (FRR) before 8.4.3 mishandles an nlri length of zero, aka a "flowspec overflow."

Published 2023-11-06 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.009 (59.4th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 59th percentile — 59.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.009 · newest: 0.009 · change: 0.000

Affected products

Frrouting

Weakness classification (CWE)

CWE-755 — Improper Handling of Exceptional Conditions

References

github.com/FRRouting/frr/pull/12884 (Patch, Issue Tracking)
github.com/FRRouting/frr/compare/frr-8.4.2...frr-8.4.3 (Patch)
lists.debian.org/debian-lts-announce/2024/04/msg00019.html (mailing-list)
af854a3a-2127-422b-91ae-364da2661108

Frequently asked questions

What is CVE-2023-38406?: CVE-2023-38406 is a critical-severity vulnerability in Frrouting, classified under Improper Handling of Exceptional Conditions. CVSS score: 9.8/10. Published 2023-11-06.
How severe is CVE-2023-38406?: Critical severity. CVSS v3 base score is 9.8 out of 10.