CVE-2021-43174Network attack vector

Service crash via gzip-expanded RRDP whitespace

Published Nov 9, 2021 · Updated Sep 16, 2024

Denial of service in NLnet Labs Routinator 0.9.0 through 0.10.1 allows remote attackers to crash the service via a malicious RRDP repository. The RRDP client accepts gzip-encoded XML and expands highly compressible whitespace into unbounded data while waiting for the next XML element. Exploitation requires Routinator to query the attacker's repository; memory exhaustion causes the operating system to terminate the process, interrupting RPKI validation.

CVSS severity7.5
High
EPSS probability1.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in NLnet Labs Routinator 0.9.0 through 0.10.1 allows remote attackers to crash the service via a malicious RRDP repository. The RRDP client accepts gzip-encoded XML and expands highly compressible whitespace into unbounded data while waiting for the next XML element. Exploitation requires Routinator to query the attacker's repository; memory exhaustion causes the operating system to terminate the process, interrupting RPKI validation.

The record

CVE
CVE-2021-43174
Published
Nov 9, 2021
Updated
Sep 16, 2024
Vendor
NLnet Labs
Product
Routinator
Classifications
CWE-1325, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 9, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <=0.10.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

NLnet Labs · Routinatorversion=unspecified <=0.10.1

Published CVSS scores

5.0NVDAV:N/AC:L/Au:N/C:N/I:N/A:P
7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-1325Improperly Controlled Sequential Memory Allocation
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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