CVE-2026-78384

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

HIGH
7.5
CVSS Score
Published: October 9, 2026 at 10:18 AM UTC
Updated: October 20, 2026 at 12:43 PM UTC
1 product affected across 1 vendorCXF

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Severity
HIGH7.5
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

95%
v < 3.6.134.0.0 ≤ v < 4.1.94.2.0 ≤ v < 4.2.44.0.04.2.0

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (2)

Vendor AdvisoryIssue Tracking
Source: cverecord
https://lists.apache.org/thread.html/xoh63rlxn0m9koft5j4jxrfd0hf81v3q
Mailing ListThird Party Advisory
Source: af854a3a-2127-422b-91ae-364da2661108
http://www.openwall.com/lists/oss-security/2026/10/09/6

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHCISA-ADP
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-409

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