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CVE-2026-59954 is an authentication bypass vulnerability affecting the Apollo ConfigService. The flaw resides in how the service authenticates requests when AccessKey or management key authentication is enabled.
The ConfigService extracts the `appId` from incoming configuration and notification requests. This `appId` is used as a key to look up the corresponding AccessKey secret from a cache. However, a logic flaw exists where the service accepts non-canonical variants of the `appId` during this authentication step.
If the extracted `appId` is a non-canonical variant, it will not match the exact canonical key used in the AccessKey cache. Consequently, ConfigService treats the request as having no associated AccessKey secrets and allows it to proceed without performing signature verification.
The vulnerability is exploitable when the downstream release lookup still resolves the non-canonical variant to the real, protected appId. This typically occurs due to database collation settings that treat different string values as equivalent. For example, this can happen with accent-insensitive collations (treating “café” and “cafe” as the same) or with PAD SPACE collations (where trailing spaces are ignored). An unauthenticated, remote attacker can exploit this discrepancy to read sensitive configuration data from endpoints like `/configs` and /configfiles. The issue is fixed in Apollo version 2.5.2.
DailyCVE Form
Platform: ……. Apollo ConfigService
Version: …….. <=2.0.1
Vulnerability :…… Authentication Bypass
Severity: ……. High (7.5)
date: ………. 2026-07-13
Prediction: ….. 2026-07-20
What Undercode Say
Root Cause Analysis: The vulnerability stems from inconsistent appId validation between the authentication and authorization layers.
Attack Vector: An attacker can modify the appId in a request to a non-canonical form (e.g., by adding trailing spaces).
Database Dependency: Successful exploitation is contingent on the database’s collation settings.
Endpoint Exposure: The primary risk is to configuration read endpoints (/configs, /configfiles).
Patch Status: The fix is available in Apollo version 2.5.2. All users are strongly advised to upgrade immediately.
Check current Apollo version Look for the version in the apollo-configservice startup logs or the JAR filename. For example: ls -la apollo-configservice-.jar Search for the presence of the vulnerability in your codebase (if self-built) Look for appId parsing logic in the authentication filter. grep -r "appId" --include=".java" | grep -i "extract|parse"
Exploit
An attacker can exploit this vulnerability by sending a request to a protected configuration endpoint with a non-canonical appId. For example, if the real `appId` is “MyApp”, the attacker could request:
/configs/MyApp /default/application
Note the trailing space after “MyApp”. If the database uses a `PAD SPACE` collation, the downstream lookup will resolve this to the real “MyApp”, but the authentication step will fail to find a matching AccessKey, thus bypassing signature verification.
Protection
Upgrade: The primary and most effective protection is to upgrade to Apollo version 2.5.2 or later.
Input Validation: As a workaround, implement strict input validation on the `appId` to reject any non-canonical variants before they reach the authentication logic.
Database Configuration: Review and harden database collation settings to prevent equivalent string matching for `appId` values.
Impact
Confidentiality Breach: An unauthenticated attacker can read sensitive configuration data, which may contain credentials, API keys, and other secrets.
Data Leakage: Exposure of configuration data can lead to further compromise of the application and its infrastructure.
Compliance Violation: Unauthorized access to configuration data can result in violations of data protection regulations (e.g., GDPR, PCI-DSS).
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Sources:
Reported By: github.com
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