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Details of issue NIXPKGS-2026-0770

NIXPKGS-2026-0770
published 3 months ago
Permalink CVE-2026-33248
4.2 MEDIUM
  • CVSS version (CVSS): 3.1
  • Attack Vector (AV): Network (N)
  • Attack Complexity (AC): High (H)
  • Privileges Required (PR): Low (L)
  • User Interaction (UI): None (N)
  • Scope (S): Unchanged (U)
  • Confidentiality (C): Low (L)
  • Integrity (I): Low (L)
  • Availability (A): None (N)
  • Modified Attack Vector (MAV): Network (N)
  • Modified Attack Complexity (MAC): High (H)
  • Modified Privileges Required (MPR): Low (L)
  • Modified User Interaction (MUI): None (N)
  • Modified Confidentiality (MC): Low (L)
  • Modified Scope (MS): Unchanged (U)
  • Modified Integrity (MI): Low (L)
  • Modified Availability (MA): None (N)
updated 2 months, 4 weeks ago by @LeSuisse Activity log
  • Created suggestion 3 months ago
  • @LeSuisse accepted 2 months, 4 weeks ago
  • @LeSuisse published on GitHub 2 months, 4 weeks ago
NATS has mTLS verify_and_map authentication bypass via incorrect Subject DN matching

NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions 2.11.15 and 2.12.6, when using mTLS for client identity, with `verify_and_map` to derive a NATS identity from the client certificate's Subject DN, certain patterns of RDN would not be correctly enforced, allowing for authentication bypass. This does require a valid certificate from a CA already trusted for client certificates, and `DN` naming patterns which the NATS maintainers consider highly unlikely. So this is an unlikely attack. Nonetheless, administrators who have been very sophisticated in their `DN` construction patterns might conceivably be impacted. Versions 2.11.15 and 2.12.6 contain a fix. As a workaround, developers should review their CA issuing practices.

Affected products

nats-server
  • ==< 2.11.15
  • ==>= 2.12.0-RC.1, < 2.12.6

Matching in nixpkgs

Package maintainers

Upstream advisory: https://github.com/nats-io/nats-server/security/advisories/GHSA-3f24-pcvm-5jqc