# CVE-2026-72756: Routinator denial of service from malformed rsync URIs

Source: https://junglewise.ai/threats/cve-2026-72756-routinator-exits-when-an-rsync-uri-for-a-file-obtained-over-rrdp  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-26. Updated: 2026-10-26  
License: CC BY 4.0 with a link back

CVE-2026-72756 · Severity: high · CVSS 7.5 · Published 2026-10-26

Routinator is an RPKI validator that fetches and validates cryptographic certificates for internet routing. When Routinator encounters an rsync URI with a file path that cannot be written to disk—such as excessively long file names or folder names that conflict with existing files—the application crashes and stops validating routes, potentially disrupting BGP security checks on networks that depend on it.

Technologies: [NLnet Labs Routinator](https://junglewise.ai/threats/technologies/routinator). Vendors: [NLnet Labs](https://junglewise.ai/threats/vendors/nlnet-labs).

## Quick answers

**Is CVE-2026-72756 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-72756 being exploited in the wild.

**How severe is CVE-2026-72756?** High severity, with a CVSS score of 7.5, published 26 October 2026.

**Which products and versions are affected?** NLnet Labs Routinator up to and including 0.15.2.

**Is there a fix for CVE-2026-72756?** Yes: fixed in Routinator 0.15.3. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-72756 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-72756?** Check whether you run NLnet Labs Routinator at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in Routinator 0.15.3

## Technical details

The vulnerability is a denial of service in Routinator's rsync URI handling: when processing an rsync reference obtained over RRDP, if the file path cannot be stored on the local filesystem (due to path length limits, name collisions, or similar filesystem constraints), the application exits instead of gracefully handling the error. An attacker can inject a malformed rsync URI into RRDP responses to trigger a crash; this requires the ability to influence RRDP data, such as via a compromised RRDP server or man-in-the-middle attack on unencrypted connections.

## Affected products

- NLnet Labs Routinator up to and including 0.15.2

## Timeline

- 2026-10-26: disclosed
- 2026-10-26: advisory

## References

- [https://www.nlnetlabs.nl/downloads/routinator/CVE-2026-72756.txt](https://www.nlnetlabs.nl/downloads/routinator/CVE-2026-72756.txt)

## Related threats

- [Routinator AS range parsing memory exhaustion](https://junglewise.ai/threats/cve-2026-72758-when-parsing-an-as-range-in-routinator-if-the-maximum-value-of)
- [Routinator HTTP server denial of service via resource exhaustion](https://junglewise.ai/threats/cve-2026-72757-routinator-runs-out-of-open-connections-on-the-http-server-when)
- [Routinator CRL parsing denial of service](https://junglewise.ai/threats/cve-2026-72754-when-routinator-encounters-a-crl-with-many-entries-it-may-hang-or)
- [Routinator improper RRDP delta entry validation](https://junglewise.ai/threats/cve-2026-72753-when-routinator-encounters-an-rrdp-notification-file-with-gaps-in)
- [NLnet Labs Routinator denial of service via repeated JSON requests](https://junglewise.ai/threats/cve-2026-72752-routinator-runs-out-of-memory-when-the-json-output-is-requested)