CVE-2026-107937

HIGH CVSS 3.1: 7.5 EPSS 0.56%
Updated Oct 16, 2026
Apache Software Foundation
Parameter Value
CVSS 7.5 (HIGH)
Affected Versions 4.0.0 — 4.2.4
Fixed In 3.6.13
Type CWE-770 (Allocation Without Limits)
Vendor Apache Software Foundation
Public PoC No

In Apache CXF, the parser for multipart/MTOM attachment part headers did not fully enforce the configured attachment-max-header-size (default 300 characters) and attachment-headers-max-count (default 500) limits. The size limit was applied only to each physical line, not to a header value built from continuation lines or to the combined values of a repeated header. The count limit was checked against the number of distinct header names, not the total number of header lines.

A remote, unauthenticated attacker could send a multipart request with very large folded or repeated part headers. The server would then allocate memory without bound, causing a denial of service. Users are recommended to upgrade to versions 4.2.4 or 4.1.9 or 3.6.13, which fix this issue.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed

Impact Assessment

Confidentiality
None
No data leak
Integrity
None
No data modification
Availability
High
Complete denial of service

CVSS Vector v3.1

Vulnerable Products 3

Configuration From (including) Up to (excluding)
Apache Cxf
cpe:2.3:a:apache:cxf:*:*:*:*:*:*:*:*
— 3.6.13
Apache Cxf
cpe:2.3:a:apache:cxf:*:*:*:*:*:*:*:*
4.0.0 4.1.9
Apache Cxf
cpe:2.3:a:apache:cxf:*:*:*:*:*:*:*:*
4.2.0 4.2.4