Description
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.
Published: 2026-10-09
Score: n/a
EPSS: n/a
KEV: No
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Remediation

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History

Fri, 09 Oct 2026 12:30:00 +0000

Type Values Removed Values Added
References

Fri, 09 Oct 2026 12:15:00 +0000

Type Values Removed Values Added
First Time appeared Apache
Apache cxf
Vendors & Products Apache
Apache cxf

Fri, 09 Oct 2026 11:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-20
CWE-400

Fri, 09 Oct 2026 10:30:00 +0000

Type Values Removed Values Added
Description 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.
Title Apache CXF: The attachment header size and count limits can be bypassed, which allows denial of service through memory exhaustion.
References

cve-icon MITRE

Status: PUBLISHED

Assigner: apache

Published:

Updated: 2026-10-09T11:07:52.472Z

Reserved: 2026-10-09T09:12:15.139Z

Link: CVE-2026-107937

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-09T11:17:02.107

Modified: 2026-10-09T12:17:09.567

Link: CVE-2026-107937

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-09T12:00:06Z

Weaknesses
  • CWE-20

    Improper Input Validation

  • CWE-400

    Uncontrolled Resource Consumption