LiveActive security incident?Get immediate response
CVE Record

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.

UnknownCVSS not scoredNot KEV-listedUpdated
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This issue can make vulnerable NLnet Labs Routinator instances run out of memory and crash while fetching RRDP repository data. For organizations relying on Routinator for RPKI validation, the business impact is availability loss in routing-security operations, not data theft based on the supplied sources.

Executive priority

Treat this as a focused availability risk for routing-security infrastructure. It is not evidenced as actively exploited, but production RPKI validators should be updated promptly because a crash can disrupt validation operations.

Technical view

Routinator 0.9.0 through 0.10.1 accepts gzip transfer encoding for RRDP. An RRDP repository can provide highly compressed XML whitespace that expands massively during parsing, exhausting memory while Routinator waits for the next XML element. The weakness is mapped to CWE-1325.

Likely exposure

Exposure is limited to environments running NLnet Labs Routinator 0.9.0 through 0.10.1 and using RRDP repository fetching. Systems packaged through Debian may also be affected if they predate DSA-5041 updates.

Exploitation context

The source bundle does not show active exploitation, and this CVE is not marked KEV. The described attacker position is an RRDP repository serving gzip-compressed content that expands excessively during Routinator processing.

Researcher notes

The supplied evidence supports denial of service via decompression expansion during RRDP XML processing. It does not provide CVSS metrics, exploit activity, or detailed fixed-version data beyond the affected range and advisory references.

Mitigation direction

  • Inventory Routinator deployments and identify versions 0.9.0 through 0.10.1.
  • Apply the relevant NLnet Labs or Debian security update guidance.
  • Prioritize systems used for production RPKI validation.
  • Monitor Routinator memory use and crash events until remediation is complete.

Validation and detection

  • Confirm installed Routinator versions are outside the affected range.
  • Check Debian hosts for DSA-5041-related package updates.
  • Review logs for recent Routinator out-of-memory crashes during RRDP fetches.
  • Verify RPKI validation service remains stable after updating.
Prepared
Confidence
high
Sources
4

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-1325: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2021-43174 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
0Timeline events
0ADP providers
3Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
NLnet LabsRoutinatorunspecifiedListed
Weakness

CWE details

CWE-1325

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-1325 · source CWE mapping

Improperly Controlled Sequential Memory Allocation

Improperly Controlled Sequential Memory Allocation represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs