CVE-2026-92877
Description
A flaw was found in jaxb-runtime. The library relies on configuration settings that do not reliably restrict XML External Entity (XXE) resolution across all underlying XML parser implementations. By supplying specially crafted XML input for unmarshalling, a remote attacker can exploit this vulnerability to read local files from the host system, resulting in information disclosure.
Statement
Red Hat Product Security has rated this issue as having a Moderate severity because exploitation requires an application to parse untrusted XML documents using specific parser backends that fail to enforce entity restrictions under secure processing mode alone. While successful exploitation can lead to unauthorized reading of local files through out-of-band XML External Entity (XXE) mechanisms, it does not allow remote code execution or modification of system data. Environments where applications do not unmarshal untrusted external XML input or where underlying XML parser implementations enforce strict external entity resolution are not exposed to this flaw.
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Application Data; Read Files or Directories
If the attacker is able to include a crafted DTD and a default entity resolver is enabled, the attacker may be able to access arbitrary files on the system. By submitting an XML file that defines an external entity with a file:// URI, an attacker can cause the processing application to read the contents of a local file. For example, a URI such as "file:///c:/winnt/win.ini" designates (in Windows) the file C:\Winnt\win.ini, or file:///etc/passwd designates the password file in Unix-based systems. Once the content of the URI is read, it is fed back into the application that is processing the XML. This application may echo back the data (e.g., in an error message), thereby exposing the file contents.
Integrity
Technical Impact: Bypass Protection Mechanism
An attacker may supply a crafted DTD using URIs with schemes such as http://, forcing the application to make outgoing HTTP requests to servers that the attacker cannot reach directly, which can be used to bypass firewall restrictions; hide the source of attacks such as port scanning; or otherwise leverage the server's trust relationship with other entities.
Availability
Technical Impact: DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory)
The product could consume excessive CPU cycles or memory using a URI that points to a large file, or a device that always returns data such as /dev/random. Alternately, the URI could reference a file that contains many nested or recursive entity references to further slow down parsing.
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