Key points
- CVE-2026-88901 affects Apache Camel versions 4.7.0 through 4.18.4 and 4.19.0 through 4.22.0.
- The flaw defaults to resolving external entities, allowing attackers to access local files or internal hosts.
- Patches are available for 4.18.5, 4.22.1, and 4.23.0, while older lines have reached end of life.
Apache Camel contains a high-severity vulnerability in its Smooks component that permits unauthorized file access and internal network probing. The flaw exists because the component resolves external XML entities by default, a behaviour that differs from other secure XML processing components within the framework.
What happened
The National Vulnerability Database records CVE-2026-88901 with a CVSS score of 8.2, classifying it as a high severity issue. This weakness stems from improper restriction of XML External Entity references within the Smooks component, known as camel-smooks. According to the vendor’s advisory, the component uses the Woodstox SAX parser by default. This parser resolves external general and parameter entities and loads external Document Type Definitions without additional hardening measures.
An attacker who can supply the XML message body to a vulnerable endpoint can exploit this default configuration. By including an external entity declaration in the XML document, the attacker forces the system to resolve and expand that entity during the unmarshalling process. This allows the attacker to read local files that are accessible to the Camel process. The source material notes that the resolved content is bound into the unmarshalled result and returned on InOut routes.
The vulnerability also enables the process to issue requests to internal network locations specified in the XML. This capability arises because the parser loads external DTDs and expands entities declared in the document. The issue affects Apache Camel versions starting from 4.7.0 up to but not including 4.18.5, and from 4.19.0 up to but not including 4.22.1. Configurations using EDI, CSV, JSON, or custom readers do not use the XML reader and remain unaffected.
Why it matters
This vulnerability matters because it requires no non-default options to exploit. The default behaviour of the camel-smooks component is to resolve external entities, which contrasts with the hardened approach used by other Camel XML components. Attackers do not need to manipulate application settings to trigger the flaw. They simply need to send a crafted XML message to an endpoint using the Smooks data format or component.
The impact includes both local file disclosure and server-side request forgery-like capabilities. An external sender whose XML reaches the affected component can cause the Camel process to request hosts named in the document. This poses a significant risk to internal network security, as the application acts as a proxy for internal requests. The source material states that this issue affects deployments that rely on the default reader for XML parsing within the Smooks integration.
What happens next
- Upgrade to Apache Camel 4.23.0, 4.22.1, or 4.18.5 to apply the vendor-provided fix.
- Move deployments on 4.14.x or earlier to a supported release, as these lines will not receive a patch.
- Review configurations to ensure they do not use the default XML reader for untrusted inputs.
- Monitor logs for unusual outbound requests or file access patterns indicative of exploitation.
Patch priority
Teams usually update systems with the highest exposure to untrusted input first. Identify endpoints that accept XML from external users and check whether they use the Smooks component with its default reader. Prioritise these systems for immediate patching. Before rolling out the update, test the fix in a staging environment to ensure compatibility with existing integrations. Back up current configurations and data to allow for quick restoration if issues arise. If an immediate upgrade is not possible, restrict XML processing to trusted sources only.
What to do and how to stay safe: Apache Camel
- Verify which Apache Camel versions are running in your environment and cross-reference them with the affected ranges.
- Check if any services use the camel-smooks component to process XML from untrusted or external senders.
- Ensure that configurations using EDI, CSV, JSON, or custom readers are correctly set, as these are not affected.
- Plan to upgrade to the latest patched version once the vendor provides an update for your specific release stream.
Step-by-step guide: Patch Management: Definition, Purpose and Operational Reality
General security guidance from the AppSec Scoop newsroom. It is not confirmed advice from the organisations named in this story.
Frequently asked questions
Which Apache Camel versions are affected by CVE-2026-88901?
Versions from 4.7.0 before 4.18.5 and from 4.19.0 before 4.22.1 are affected by this vulnerability.
Is there a patch available for this vulnerability?
Yes, users can upgrade to Apache Camel 4.18.5, 4.22.1, or 4.23.0 to fix the issue.
Do all configurations of the Smooks component suffer from this flaw?
No, configurations that declare their own reader, such as EDI, CSV, JSON, or custom readers, are not affected.
