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

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-11-09 · updated 2026-06-17
Weakness: CWE-1325

Description

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.

Affected products

Debian Linux: 11.0
NLnet Labs Routinator: from 0.9.0 before 0.10.2 — fixed in 0.10.2

How to fix

Upgrade to a fixed version: NLnet Labs Routinator 0.10.2. Check the vendor advisory for mitigations.

References

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