CVE-2026-42602 PUBLISHED

azureauthextension Authenticate method does not validate bearer tokens, allowing auth bypass via replay

Assigner: GitHub_M
Reserved: 29.04.2026 Published: 13.05.2026 Updated: 13.05.2026

azureauthextension is the Azure Authenticator Extension. From 0.124.0 to 0.150.0, a server-side authentication bypass in azureauthextension allows any party who holds a single valid Azure access token for any scope the collector's configured identity can mint for to authenticate to any OpenTelemetry receiver that uses auth: azure_auth. The extension's Authenticate method does not validate incoming bearer tokens as JWTs. Instead, it calls its own configured credential to obtain an access token and compares the client's token to the result with string equality — and the scope for that server-side token request is taken from the client-supplied Host header. As a result, a token minted for any Azure resource the service principal has ever been issued a token for (ARM, Graph, Key Vault, Storage, etc.) will authenticate to the collector if the attacker picks a matching Host. Tokens are replayable for the full issued lifetime (commonly several hours for managed identity tokens).

Metrics

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
CVSS Score: 8.1

Product Status

Vendor open-telemetry
Product opentelemetry-collector-contrib
Versions
  • Version >= 0.124.0, <= 0.150.0 is affected

References

Problem Types

  • CWE-208: Observable Timing Discrepancy CWE
  • CWE-287: Improper Authentication CWE
  • CWE-290: Authentication Bypass by Spoofing CWE
  • CWE-294: Authentication Bypass by Capture-replay CWE
  • CWE-347: Improper Verification of Cryptographic Signature CWE