Vulnerability · Published May 13, 2026 · Assigned by GitHub_M
CVE-2026-42602azureauthextension Authenticate method does not validate bearer tokens, allowing auth bypass via replay
High 8.1
In plain English
A high-severity improper authentication in opentelemetry-collector-contrib from open-telemetry. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 13% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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).
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | github.com/open-telemetry/opentelemetry-collector-contrib/extension/azureauthextension | no fix listed | GHSA-pjv4-3c63-699f |
| Go | github.com/open-telemetry/opentelemetry-collector-contrib/extension/azureauthextension | 0.151.0 | GO-2026-5544 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| open-telemetry | opentelemetry-collector-contrib | >= 0.124.0, <= 0.150.0 |
Weakness: CWE-208, CWE-287, CWE-290, CWE-294, CWE-347 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H