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Fencer Intel
medium 4.4

CVE-2021-3909 json

Infinite open connection causes OctoRPKI to hang forever

published 4y ago modified 4mo ago also GHSA-8cvr-4rrf-f244 , GO-2022-0250 , EUVD-2021-2322

cvss
4.4
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.6%
EPSS 1.6% chance of exploitation in 30 days, percentile 75%
public exploits
0
none known

Summary

OctoRPKI does not limit the length of a connection, allowing for a slowloris DOS attack to take place which makes OctoRPKI wait forever. Specifically, the repository that OctoRPKI sends HTTP requests to will keep the connection open for a day before a response is returned, but does keep drip feeding new bytes to keep the connection alive.

Patch / fix

  • go github.com/cloudflare/cfrpki 1.4.0
  • Cloudflare octorpki 1.4.0
  • cfrpki Debian 12 1.4.0-1
  • rpki-client Debian 14, Debian 13, Debian 12 7.5-1
  • fort-validator Debian 14, Debian 13, Debian 12 1.5.3-1

debian advisories DEBIAN-CVE-2021-3909

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Exploit prediction

1.58% chance of exploitation in the next 30 days, higher than 75% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 4.4 CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P
GitHub 3.1 4.4 CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
go github.com/cloudflare/cfrpki
<1.4.0
1.4.0

Affected products

  • Cloudflare octorpki

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.