CVE-2021-43174 | gzip transfer encoding caused out-of-memory crash

NLnet Labs Routinator versions 0.9.0 up to and including 0.10.1, support the gzip transfer encoding when querying RRDP repositories. This encoding can be used by an RRDP repository to cause an out-of-memory crash in these versions of Routinator. RRDP uses XML which allows arbitrary amounts of white space in the encoded data. The gzip scheme compresses such white space extremely well, leading to very small compressed files that become huge when being decompressed for further processing, big enough that Routinator runs out of memory when parsing input data waiting for the next XML element.

Published: 2021-11-09 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-43174 is rated Moderate Risk (52.5/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.17%). 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-2021-43174

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 0.72% 1.17% +0.45%
2 2025-11-21 0.62% 0.72% +0.10%
3 2025-11-18 — 0.62% —

Full EPSS history (13 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-43174

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
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-2021-43174

GitHub Security Advisory for CVE-2021-43174

OS Trackers for CVE-2021-43174

vendor priority summary link
debian not yet assigned CVE-2021-43174 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-2021-43174
ubuntu low CVE-2021-43174 low priority: Ubuntu including 2 source packages (cfrpki, routinator), 8 status rows across 5 suites (impish, jammy, trusty, upstream, xenial): ignored 5, needs-triage 1, not-affected 1, released 1. https://ubuntu.com/security/CVE-2021-43174

Affected software / configurations for CVE-2021-43174

Vendor Product Version Raw CPE
nlnetlabs routinator >= 0.9.0, < 0.10.2 cpe:2.3:a:nlnetlabs:routinator:*:*:*:*:*:*:*:*
debian debian_linux 11.0 cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*

References for CVE-2021-43174

cvelogic Threat Intelligence