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CVE-2026-78384

Apache CXF: Unbounded DEFLATE Decompression in CXF JOSE/JWE and SAML Processing (Decompression Bomb)

Apache Software Foundation Apache CXF
Open in ThreatlineRecord JSON
CVSS
7.5High
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.37%Chance of exploitation activity in the next 30 days, higher than 29% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in4.2.4Also 4.1.9, 3.6.13CVE List
Published9 Oct 2026Updated 15 Oct 2026CVE List

What fixes it

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

Description

CompressionUtils.inflate() decompressed attacker-controlled DEFLATE data with no output-size cap. A small (~KB) crafted payload could expand to gigabytes on the heap. Reachable via JWE decryption when zip=DEF (e.g. JoseSessionTokenProvider with RSA-OAEP key wrap) and via SAML redirect/POST binding token inflation — in both cases decompression happens before/independent of trust validation.

Fix: Added a configurable maximum inflated-size cap (default 10 MiB, org.apache.cxf.compression-max-inflated-size system property) to CompressionUtils.inflate(); aborts with DataFormatException once exceeded. Users are recommended to upgrade to versions 4.2.4 or 4.1.9 or 3.6.13, which fix this issue.

Text from CVE List

Affected versions 3

  • Apache CXFaffected: 4.2.0 before 4.2.4CVE List
  • Apache CXFaffected: 4.0.0 before 4.1.9CVE List
  • Apache CXFaffected: all versions before 3.6.13CVE List

References 1