CVE-2026-90797: Apache CouchDB: Pre-authentication gzip decompression bomb via POST /_session

Severity: high (CVSS 7.7 v4.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-20 · updated 2026-10-20
Weakness: CWE-409

Description

An unlimited gzip decompression routine in chttpd in Apache CouchDB 3.5.2 and below on all platforms allows any remote client to cause a denial of service via memory exhaustion. Users are recommended to upgrade to version 3.5.3, which fixes this issue.

Affected products

Apache Software Foundation Apache CouchDB: before 3.5.3 — fixed in 3.5.3

How to fix

Upgrade to a fixed version: Apache Software Foundation Apache CouchDB 3.5.3. Check the vendor advisory for mitigations.

References

https://lists.apache.org/thread.html/pj83174r8f8f64odf47fwhozbfjtot0f
https://lists.apache.org/thread/gsbotof0qn8x6zlpd7t568ny4053jo0n
http://www.openwall.com/lists/oss-security/2026/10/20/12

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