Apache CXF: Improper Restriction of XML External Entity Reference
CVE-2026-49875 is a critical-severity improper restriction of XML external entity reference vulnerability in Apache CXF from Apache, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 4.2.2, 4.1.7, 3.6.12 as the first without the flaw, so updating Apache CXF to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.53% chance of exploitation within 30 days, which is low compared with other CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update Apache CXF to 4.2.2 or 4.1.7 or 3.6.12, whichever matches your release line, or a later version.
- Update Cxf to 3.6.12 or 4.1.7 or 4.2.2, whichever matches your release line, or a later version.
- Update Jboss Enterprise Application Platform to 8.1.8 or a later version.
- Read the advisory on lists.apache.org for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Apache | Apache CXF | 4.2.0 up to, but not including, 4.2.2; 4.0.0 up to, but not including, 4.1.7; before 3.6.12 | 4.2.2, 4.1.7, 3.6.12 |
| Red Hat | Red Hat build of Apache Camel 4.18.1.P1 for Spring Boot 3.5.16 | Not specified in the record | Not stated |
| Red Hat | Red Hat Build of Apache Camel 4.18 for Quarkus 3.33 | Not specified in the record | Not stated |
| Red Hat | Red Hat build of Apache Camel 4 for Quarkus 3 | Not specified in the record | Not stated |
| Red Hat | Red Hat Fuse 7 | Not specified in the record | Not stated |
| Red Hat | Red Hat JBoss Enterprise Application Platform 7 | Not specified in the record | Not stated |
| Red Hat | Red Hat JBoss Enterprise Application Platform 8 | Not specified in the record | Not stated |
| Red Hat | Red Hat JBoss Enterprise Application Platform Expansion Pack | Not specified in the record | Not stated |
| Red Hat | Red Hat JBoss Web Server 5 | Not specified in the record | Not stated |
| Red Hat | Red Hat Single Sign-On 7 | Not specified in the record | Not stated |
| Apache | Cxf | before 3.6.12; 4.0.0 up to, but not including, 4.1.7; 4.2.0 up to, but not including, 4.2.2 | 3.6.12, 4.1.7, 4.2.2 |
| Red Hat | Jboss Enterprise Application Platform | 8.1 up to, but not including, 8.1.8; 7.0 | 8.1.8 |
| Red Hat | Build Of Apache Camel | before 3.33.2; before 4.18.1; 3.33.2; 4.18.1 | 3.33.2, 4.18.1 |
| Red Hat | Fuse | 7.0.0 | Not stated |
| Red Hat | Jboss Web Server | 5.0 | Not stated |
| Red Hat | Single Sign-on | 7.0 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 9.8 | Critical | NVD |
| CVSS 3.1 | 6.5 | Medium | CISA (ADP) |
| CVSS 3.1 | 7.5 | High | CNA |
Official description
Apache CXF's EndpointReferenceUtils and W3CMultiSchemaFactory classes construct a SAXParserFactory without the necessary JAXP hardening configurations, enabling out-of-band (OOB) external entity resolution. Users are recommended to upgrade to versions 4.2.2 or 4.1.7 or 3.6.12, which fix this issue.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Restriction of XML External Entity Reference
The product processes an XML document that can contain XML entities with URIs that resolve to documents outside of the intended sphere of control, causing the product to embed incorrect documents into its output.
How developers prevent this class of flaw
- Many XML parsers and validators can be configured to disable external entity expansion.
More Improper Restriction of XML External Entity Reference vulnerabilities (CWE-611)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- openwall.com/lists/oss-security/2026/06/11/2Mailing List, Third Party Advisory
- access.redhat.com/errata/RHSA-2026:36839Third Party Advisory
- access.redhat.com/errata/RHSA-2026:37390Third Party Advisory
- access.redhat.com/security/cve/CVE-2026-49875Third Party Advisory
- bugzilla.redhat.com/show_bug.cgi?id=2488309Issue Tracking, Third Party Advisory
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-49875.jsonThird Party Advisory
Other vulnerabilities in Apache CXF
- 7.5 High severity
- 9.1 Critical severity
- 7.5 High severity
- 7.5 High severity
- 8.1 High severity
- 9.1 Critical severity
Recent Improper Restriction of XML External Entity Reference vulnerabilities
- 8.2 High severity
- 7.4 High severity
- 7.7 High severity
- 7.1 High severity
- 7.5 High severity
- 8.1 High severity
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