CVE-2021-3761
Publication date 9 September 2021
Last updated 25 August 2025
Ubuntu priority
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.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| cfrpki | 24.04 LTS noble | Not in release |
| 22.04 LTS jammy |
Not affected
|
|
| 20.04 LTS focal | Not in release | |
| 18.04 LTS bionic | Not in release | |
| 16.04 LTS xenial | Ignored end of standard support | |
| 14.04 LTS trusty | Not in release |
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score |
7.5 · High
|
| Attack vector | Network |
| Attack complexity | Low |
| Privileges required | None |
| User interaction | None |
| Scope | Unchanged |
| Confidentiality | None |
| Integrity impact | None |
| Availability impact | High |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |