High severity · published Oct 9, 2026
CVE-2026-78384
Apache CXF: Unbounded DEFLATE Decompression in CXF JOSE/JWE and SAML Processing (Decompression Bomb)
7.5
CVSS
0.4%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 31% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
AC
Apache CXF · Apache Software Foundation
4.2.0 before 4.2.4; 4.0.0 before 4.1.9; before 3.6.13 · source: vendor
CX
Cxf · Apache
before 3.6.13; 4.0.0 before 4.1.9; 4.2.0 before 4.2.4 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-78384
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-78384
vendor-advisory
https://lists.apache.org/thread.html/xoh63rlxn0m9koft5j4jxrfd0hf81v3q
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