cloudflare octorpki CVE-2021-3761 in CloudFlare and Debian Products
Published on September 9, 2021

OctoRPKI lacks contextual out-of-bounds check when validating RPKI ROA maxLength values

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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.

Github Repository Vendor Advisory NVD

Vulnerability Analysis

CVE-2021-3761 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.

Attack Vector:
NETWORK
Attack Complexity:
LOW
Privileges Required:
NONE
User Interaction:
NONE
Scope:
UNCHANGED
Confidentiality Impact:
NONE
Integrity Impact:
NONE
Availability Impact:
HIGH

Products Associated with CVE-2021-3761

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CloudFlare Octorpki
 
Debian Linux
 

Affected Versions

Cloudflare octorpki:

Exploit Probability

EPSS
1.18%
Percentile
63.55%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.