How severe is CVE-2021-41531?

CVE-2021-41531 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2021-41531 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (55th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-41531?

CVE-2021-41531 affects Nlnetlabs Routinator. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-41531?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-41531 published?

CVE-2021-41531 was published on 2021-09-21 and last updated on 2026-06-17.

CVE-2021-41531

CVE-2021-41531 is a high-severity vulnerability in Nlnetlabs Routinator with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-20.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 1% (55th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Nlnetlabs Routinator
Published: 2021-09-21
Last modified: 2026-06-17

Description

NLnet Labs Routinator prior to 0.10.0 produces invalid RTR payload if an RPKI CA uses too large values in the max-length parameter in a ROA. This will lead to RTR clients such as routers to reject the RPKI data set, effectively disabling Route Origin Validation.

Frequently asked questions

What is CVE-2021-41531?: NLnet Labs Routinator prior to 0.10.0 produces invalid RTR payload if an RPKI CA uses too large values in the max-length parameter in a ROA. This will lead to RTR clients such as routers to reject the RPKI data set, effectively disabling Route Origin Validation.
How severe is CVE-2021-41531?: CVE-2021-41531 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2021-41531 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (55th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-41531?: CVE-2021-41531 affects Nlnetlabs Routinator. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-41531?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-41531 published?: CVE-2021-41531 was published on 2021-09-21 and last updated on 2026-06-17.

References

https://www.nlnetlabs.nl/downloads/routinator/CVE-2021-41531.txt

Affected products (1)

cpe:2.3:a:nlnetlabs:routinator:*:*:*:*:*:*:*:*

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