Description

Cross-repository issue/comment attachment re-linking can expose private attachment content

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "5.9",
  "pubDate": "2026-08-13T17:17:25.863Z",
  "pubdate": "2026-08-13T17:17:25.863Z",
  "executiveSummary": "A vulnerability exists in cross-repository issue and comment attachment re-linking functionality that can expose private attachment content to unauthorized users.\nThe vulnerability class involves improper access control and authorization enforcement during attachment referencing across distinct code repositories.\nThe primary impact is the unauthorized disclosure of sensitive or private attachment data, potentially compromising confidential intellectual property, credentials, or internal operational details stored within restricted attachments.\nThe risk implications are significant for organizations handling sensitive artifacts in private or internal repositories, as unauthorized actors may gain visibility into data they are not privileged to access.\nAn attacker requires the ability to interact with issue tracking or commenting systems where cross-repository references are processed and re-linked.\nExploitation requirements typically involve crafting specific references or inputs that trigger the application's re-linking mechanism, forcing it to resolve and render attachments from private contexts into unauthorized viewing channels without proper permission validation.",
  "technicalDetails": "The root cause of this vulnerability lies in the insufficient validation of access permissions when the application performs cross-repository attachment re-linking.\nWhen a user references an attachment or asset from one repository within the context of another—such as in an issue description or comment—the backend processing routine often resolves and displays the attachment without verifying whether the requesting user possesses explicit read access to the originating repository or private attachment resource.\nThe vulnerable component resides within the attachment handling and reference parsing subsystem responsible for mapping URLs or internal identifiers to stored binary assets.\nThe attack flow begins when an attacker identifies or guesses the identifier of a private attachment residing in a restricted repository.\nThe attacker then crafts a comment or issue within a public or authorized repository under their control, incorporating a reference pattern that triggers the cross-repository re-linking logic.\nUpon ingestion and rendering of the issue or comment, the application evaluates the reference, retrieves the underlying attachment content from storage, and embeds or displays it in a context accessible to the attacker or victims.\nBecause authorization checks are bypassed or inadequately scoped to the source repository during the re-linking phase, the private content is successfully served.\nNetwork exposure typically spans web interfaces and API endpoints handling issue creation, comment submission, and Markdown or rich-text rendering.\nAuthentication and privilege requirements depend on the platform configuration, but exploitation frequently allows lower-privileged users or external actors to bypass boundary controls separating private and public repositories.\nThe post-exploitation impact includes unauthorized exfiltration of sensitive data contained within attachments, such as proprietary source code snippets, configuration files, internal architecture diagrams, or personally identifiable information."
}