CVE-2021-3909
Infinite open connection causes OctoRPKI to hang forever
CVE-2021-3909 is a medium vulnerability (CVSS 4.4) in Cloudflare Octorpki, published November 10, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.57%, the 75th percentile. Fixed in github.com/cloudflare/cfrpki 1.4.0.
- Severity
- 4.4 MediumCVSS 3.1, CVE List
- Exploit chance
- 1.57%EPSS, 75th percentile
- Exploitation
- None knownNot on CISA’s or ENISA’s lists
- Fixed in
1.4.0github.com/cloudflare/cfrpki +9 more
Description
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- High
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
github.com/cloudflare/cfrpkiGo | before 1.4.0 | 1.4.0 |
cfrpkiDebian:12 | before 1.4.0-1 | 1.4.0-1 |
fort-validatorDebian:12 | before 1.5.3-1 | 1.5.3-1 |
fort-validatorDebian:13 | before 1.5.3-1 | 1.5.3-1 |
fort-validatorDebian:14 | before 1.5.3-1 | 1.5.3-1 |
rpki-clientDebian:12 | before 7.5-1 | 7.5-1 |
rpki-clientDebian:13 | before 7.5-1 | 7.5-1 |
rpki-clientDebian:14 | before 7.5-1 | 7.5-1 |
fort-validatorDebian:11 From an advisory covering 4 CVEs | before 1.5.3-1~deb11u1, plus listed versions 1.5.0-11.5.1-11.5.2-1 | 1.5.3-1~deb11u1 |
cfrpkiDebian:11 From an advisory covering 10 CVEs | before 1.4.2-1~deb11u1, plus listed versions 1.2.2-11.3.0-11.4.0-1 | 1.4.2-1~deb11u1 |
What each source reports
CVE List Score used
Infinite open connection causes OctoRPKI to hang forever
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.
- Record
CVE-2021-3909- CVSS 3.1
- 4.4 Medium
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-400
- Updated
- 2026-11-02
EUVDEUVD-2021-2322
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.
- Record
EUVD-2021-2322- CVSS 3.1
- 4.4 Medium
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-8cvr-4rrf-f244
Infinite open connection causes OctoRPKI to hang forever
OctoRPKI (github.com/cloudflare/cfrpki/cmd/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.
Patches
For more information
If you have any questions or comments about this advisory email us at security@cloudflare.com
- Record
GHSA-8cvr-4rrf-f244- CVSS 3.1
- 4.4 Medium
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-400
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2021-3909- CVSS 3.1
- 4.4 Medium
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H - CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - CVSS 2.0
- 5.0 Medium
AV:N/AC:L/Au:N/C:N/I:N/A:P - Weakness
- CWE-400
- Updated
- 2026-11-02
OSV
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.
- Record
CVE-2021-3909- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVDEBIAN-CVE-2021-3909
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.
- Record
DEBIAN-CVE-2021-3909- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVGHSA-8cvr-4rrf-f244
Infinite open connection causes OctoRPKI to hang forever
OctoRPKI (github.com/cloudflare/cfrpki/cmd/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.
Patches
For more information
If you have any questions or comments about this advisory email us at security@cloudflare.com
- Record
GHSA-8cvr-4rrf-f244- CVSS 3.1
- 4.4 Medium
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-400
- Updated
- 2026-11-02
OSVUBUNTU-CVE-2021-3909
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.
- Record
UBUNTU-CVE-2021-3909- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - CVSS 3.1
- 4.4 Medium
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVGO-2022-0250No score
Infinite open connection causes OctoRPKI to hang forever in github.com/cloudflare/cfrpki
Infinite open connection causes OctoRPKI to hang forever in github.com/cloudflare/cfrpki
- Record
GO-2022-0250- Updated
- 2026-11-02
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, facts | ||
| affected | ||
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.