CVE-2026-107937

Apache CXF: The attachment header size and count limits can be bypassed, which allows denial of service through memory exhaustion.

Published Oct 9, 2026 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
CPEs cpe:2.3:a:apache:cxf:*:*:*:*:*:*:*:*
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Weaknesses CWE-770
References
Metrics threat_severity

None

cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Important

Type Values Removed Values Added
First Time appeared Apache
Apache cxf
Vendors & Products Apache
Apache cxf
Type Values Removed Values Added
Weaknesses CWE-20
CWE-400
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
Weaknesses

Sources

Status
PUBLISHED
Assigner
apache
Published
Updated
Oct 15, 2026, 5:45 PM
Reserved
Oct 9, 2026, 9:12 AM
Status
Analyzed
Published
Oct 9, 2026, 11:17 AM
Modified
Oct 16, 2026, 6:10 PM
Severity
Important
Public date
Oct 9, 2026, 10:19 AM