oss-security - CVE-2026-78384: Apache CXF: Unbounded DEFLATE Decompression in CXF JOSE/JWE and SAML Processing (Decompression Bomb)

Follow @Openwall on Twitter for new release announcements and other news

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <a6135355-3162-fbe6-ef83-f645a2b0866c@apache.org>
Date: Fri, 09 Oct 2026 09:52:54 +0000
From: Colm O hEigeartaigh <coheigea@...che.org>
To: oss-security@...ts.openwall.com
Subject: CVE-2026-78384: Apache CXF: Unbounded DEFLATE Decompression in CXF
 JOSE/JWE and SAML Processing (Decompression Bomb) 

Severity: moderate 

Affected versions:

- Apache CXF (org.apache.cxf:cxf-core) 4.2.0 before 4.2.4
- Apache CXF (org.apache.cxf:cxf-core) 4.0.0 before 4.1.9
- Apache CXF (org.apache.cxf:cxf-core) before 3.6.13

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.

Credit:

Guanping Zhang reported this vulnerability. (finder)

References:

https://cxf.apache.org/
https://www.cve.org/CVERecord?id=CVE-2026-78384

Please check out the Open Source Software Security Wiki, which is counterpart to this mailing list.

Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.