Apache CXF CompressionUtils Inflate Decompression Bomb (Zip Bomb)
CVE-2026-78384 Published on October 9, 2026
Apache CXF: Unbounded DEFLATE Decompression in CXF JOSE/JWE and SAML Processing (Decompression Bomb)
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.
Vulnerability Analysis
CVE-2026-78384 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have a high impact on confidentiality, with no impact on integrity and availability.
Weakness Type
What is a Data Amplification Vulnerability?
The software does not handle or incorrectly handles a compressed input with a very high compression ratio that produces a large output. An example of data amplification is a "decompression bomb," a small ZIP file that can produce a large amount of data when it is decompressed.
CVE-2026-78384 has been classified to as a Data Amplification vulnerability or weakness.
Products Associated with CVE-2026-78384
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Affected Versions
Apache Software Foundation Apache CXF:- Version 4.2.0 and below 4.2.4 is affected.
- Version 4.0.0 and below 4.1.9 is affected.
- Before 3.6.13 is affected.