Routinator infinite loop vulnerability

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

• CVE-2021-43172: 1.10% estimated exploitation activity in the next 30 days; percentile 65.79 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

NLnet Labs Routinator prior to 0.10.2 happily processes a chain of RRDP repositories of infinite length causing it to never finish a validation run. In RPKI, a CA can choose the RRDP repository it wishes to publish its data in. By continuously generating a new child CA that only consists of another CA using a different RRDP repository, a malicious CA can create a chain of CAs of de-facto infinite length. Routinator prior to version 0.10.2 did not contain a limit on the length of such a chain and will therefore continue to process this chain forever. As a result, the validation run will never finish, leading to Routinator continuing to serve the old data set or, if in the initial validation run directly after starting, never serve any data at all.

Published by the source

24 May 2022, 19:20 UTC

Last modified by the source

13 Jul 2023, 17:03 UTC

Source last checked

26 Oct 2026, 15:37 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-m3x9-623g-35c4

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# Patch Next advisory brief: CVE-2021-43172

Advisory: Routinator infinite loop vulnerability
IDs: CVE-2021-43172, GHSA-m3x9-623g-35c4
Record: https://patchnext.com/advisories/cve-2021-43172 (revision 1, source checked 26 Oct 2026, 15:37 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: routinator 0.10.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- crates.io routinator: affected < 0.10.2; fixed in 0.10.2

## Suggested inspection (read-only)
- crates.io routinator: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on routinator.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-m3x9-623g-35c4 (GitHub-reviewed advisory GHSA-m3x9-623g-35c4 lists affected ranges: crates.io routinator >=0 <0.10.2)

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