CVE-2026-107937: Apache Software Foundation Apache Cxf

EPSS: 0.2% chance of exploitation in the next 30 days.

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.

Affected products

• Apache Software Foundation Apache Cxf: from 4.2.0, before 4.2.4 (fixed in 4.2.4); from 4.0.0, before 4.1.9 (fixed in 4.1.9); before 3.6.13 (fixed in 3.6.13)

Published 2026-10-09. Last modified 2026-10-09.