Description

In JetBrains IntelliJ IDEA before 2026.3, 2026.2.4 sSRF was possible via annotations.xml files during indexing

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "3.3",
  "pubDate": "2026-11-06T11:17:10.460Z",
  "pubdate": "2026-11-06T11:17:10.460Z",
  "executiveSummary": "A Server-Side Request Forgery (SSRF) vulnerability exists in JetBrains IntelliJ IDEA versions prior to 2026.3 and 2026.2.4.\nThe vulnerability occurs during the IDE's automated project indexing process when processing 'annotations.xml' configuration files.\nAn attacker can exploit this flaw by crafting malicious entries within 'annotations.xml', which the IDE parses with insufficient validation.\nSuccessful exploitation allows an attacker to induce the IDE to perform unauthorized outbound HTTP or network requests from the local environment.\nThis can be leveraged to interact with internal network services, bypass firewall restrictions, or perform service discovery on the host machine or local network infrastructure.\nThe impact depends on the internal network exposure and the sensitivity of services reachable from the IDE's host machine.\nExploitation requires the attacker to influence the project's 'annotations.xml' file, typically achieved through project sharing, importing untrusted code, or persistent repository manipulation.",
  "technicalDetails": "The vulnerability resides in the indexing mechanism of IntelliJ IDEA, specifically within the module responsible for parsing and processing 'annotations.xml' metadata files.\nDuring the project indexing phase, IntelliJ IDEA inspects 'annotations.xml' to apply external annotations to the codebase. The parsing logic fails to adequately sanitize or validate URI-based attributes or resource pointers defined within these files.\nWhen the IDE encounters a crafted 'annotations.xml' file containing malicious URI schemes or targets, the underlying network client processes these inputs without implementing proper URL blacklisting or destination filtering.\nAttack flow: An attacker introduces a modified 'annotations.xml' into the project's configuration directory. Upon opening or refreshing the project, the IDE triggers an automatic indexing task. As the indexer parses the malicious XML structure, it extracts the URI and initiates an outbound connection attempt.\nBecause the IDE operates with the privileges of the logged-in user, the forged request is executed from the local machine. This allows the request to bypass NAT/Firewall boundaries that might otherwise protect internal resources from external traffic.\nThe vulnerability is primarily triggered during the automated background indexing phase, meaning user interaction beyond the initial project loading may not be required for the request to be dispatched.\nThe technical root cause is an improper neutralization of input used in resource location, leading to SSRF. The lack of validation on the target host and port allows the IDE to function as a proxy for internal network reconnaissance or interaction with metadata services (such as cloud-instance metadata endpoints).\nAffected versions include all releases prior to 2026.3 and 2026.2.4. Authentication or specific privilege escalation is not required if the attacker can place the malicious configuration file within a project workspace that is subsequently loaded by the vulnerable IDE instance."
}