CVE-2021-3908 | Infinite certificate chain depth results in OctoRPKI running forever

OctoRPKI does not limit the depth of a certificate chain, allowing for a CA to create children in an ad-hoc fashion, thereby making tree traversal never end.

Published: 2021-11-11 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-3908 is rated Moderate Risk (41/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.71%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-3908

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.29% 0.71% +0.42%
2 2025-11-21 0.19% 0.29% +0.10%
3 2025-11-18 — 0.19% —

Full EPSS history (16 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-3908

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.9 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.2 3.6 [email protected]
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2021-3908

GitHub Security Advisory for CVE-2021-3908

GHSA-g5gj-9ggf-9vmq · Severity: medium · Ecosystem: go — Infinite certificate chain depth results in OctoRPKI running forever

OS Trackers for CVE-2021-3908

vendor priority summary link
debian not yet assigned CVE-2021-3908 not yet assigned priority: Debian including 1 source packages (cfrpki), 2 status rows across 2 suites (bookworm, bullseye): resolved 2. https://security-tracker.debian.org/tracker/CVE-2021-3908
ubuntu medium CVE-2021-3908 medium priority: Ubuntu including 1 source packages (cfrpki), 10 status rows across 10 suites (hirsute, impish, jammy, kinetic, lunar, mantic, noble, trusty, upstream, xenial): ignored 7, DNE 1, not-affected 1, released 1. https://ubuntu.com/security/CVE-2021-3908

Affected software / configurations for CVE-2021-3908

Vendor Product Version Raw CPE
cloudflare octorpki < 1.3.0 cpe:2.3:a:cloudflare:octorpki:*:*:*:*:*:*:*:*
debian debian_linux 11.0 cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*

References for CVE-2021-3908

cvelogic Threat Intelligence