---
id: CVE-2026-107937
title: >-
  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
summary: >-
  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 appli…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-770
vendor: apache
product: cxf
affected:
  - cxf < 3.6.13
  - 'cxf >= 4.0.0, < 4.1.9'
  - 'cxf >= 4.2.0, < 4.2.4'
patched:
  - cxf 4.2.4
published: '2026-10-09'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T18:10:19.410'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-107937'
references:
  - url: 'https://lists.apache.org/thread.html/x9twtpv3d04qj83t6w9xkh9y2q28zztj'
    label: security@apache.org
  - url: 'http://www.openwall.com/lists/oss-security/2026/10/09/12'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-107937.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-107937'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2548463'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-107937'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-107937'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
epss: 0.00556
epssPercentile: 0.4617
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-10-15T17:45:18.146774Z'
ingestedAt: '2026-10-09T12:53:29.299Z'
---

## Overview

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

- `cxf < 3.6.13`
- `cxf >= 4.0.0, < 4.1.9`
- `cxf >= 4.2.0, < 4.2.4`

## Remediation

Upgrade past the affected range:

- `cxf 4.2.4`

## Vendor advisories

- **Red Hat VEX** · Important · affected: Red Hat build of Apache Camel 4 for Quarkus 3, Red Hat build of Apache Camel for Spring Boot 4, Red Hat Fuse 7, Red Hat JBoss Enterprise Application Platform 7, Red Hat JBoss Enterprise Application Platform 8, Red Hat JBoss Web Server 5, … · no fix planned: Red Hat JBoss Enterprise Application Platform 7, Red Hat JBoss Web Server 5, Red Hat Single Sign-On 7, Red Hat build of Apache Camel 4 for Quarkus 3, … · updated 2026-10-16 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-107937.json)