CVE-2021-3761
An attacker can use this to disable RPKI Origin Validation in a victim network (for example AS 13335 - Cloudflare) prior to launching a BGP hijack which during normal operations would be rejected as "RPKI invalid".
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.22%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
Any CA issuer in the RPKI can trick OctoRPKI prior to 1.3.0 into emitting an invalid VRP "MaxLength" value, causing RTR sessions to terminate. An attacker can use this to disable RPKI Origin Validation in a victim network (for example AS 13335 - Cloudflare) prior to launching a BGP hijack which during normal operations would be rejected as "RPKI invalid". Additionally, in certain deployments RTR session flapping in and of itself also could cause BGP routing churn, causing availability issues.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 1.22% probability · 67th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-787
- Affected
- cloudflare/octorpki · debian/debian linux
- Source
- cna@cloudflare.com
References
- https://github.com/cloudflare/cfrpki/security/advisories/GHSA-c8xp-8mf3-62h9Patch, Third Party Advisory
- https://www.debian.org/security/2022/dsa-5041Third Party Advisory
- https://github.com/cloudflare/cfrpki/security/advisories/GHSA-c8xp-8mf3-62h9Patch, Third Party Advisory
- https://www.debian.org/security/2022/dsa-5041Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.