7.5

CVE-2021-3761: cloudflare octorpki Out-of-bounds Write

CVSS: 7.5v3.1HighModified
AliasesUBUNTU-CVE-2021-3761DEBIAN-CVE-2021-3761GHSA-c8xp-8mf3-62h9
Published 09-09-2021Last modified 17-09-2024
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Vulnerability summary

CVE-2021-3761 is a high (CVSS 7.5) Out-of-bounds Write vulnerability in cloudflare octorpki. EPSS estimates a 1.22% chance of exploitation in the next 30 days, higher than 68.1% of scored vulnerabilities.

Overall risk
30/100
0100
Medium · default modelHow is this calculated?
CVSS score
7.5/10
010
High · v3.1 (CVE.org)
EPSS score
1.22%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 1
DSA-5041-1

Timeline

  1. 09-09-2021
    PublishedVulnerability first disclosed.
  2. 17-09-2024
    Last modifiedVulnerability information updated.

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 metrics

6 scores · 5 sources · 2 versions

EPSS trend

Probability

1.22%

Chance of exploitation in the next 30 days

Percentile

68%

Versus all other CVEs

30-day change

0.00 pp

From 1.22% on 19-09-2026

19-09-202619-10-2026
EPSS score
1.22%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Debian2 products
Cloudflare1 product
  • octorpki≥ unspecified, < 1.3.0 | < 1.3.0
Github.com/cloudflare1 product
  • cfrpki< 1.3.0
Ubuntu1 product
  • cfrpki< 1.4.2-1

4 vendors · 5 products

References

10 links