CVE-2025-61926: 
vulnerability analysis and mitigation

CVE-2025-61926 affects Allstar, a GitHub App designed for setting and enforcing security policies. The vulnerability was discovered in the Reviewbot component and disclosed on October 9, 2025. The issue affects all Allstar releases prior to version 4.5 that include the Reviewbot code path (GitHub Advisory).

The vulnerability stems from the Reviewbot component using a hard-coded, shared secret for validating inbound webhook requests. The secret token was compiled into the Allstar binary and could not be configured at runtime. This implementation flaw is classified under CWE-453 (Insecure Default Variable Initialization) and CWE-798 (Use of Hard-coded Credentials). The vulnerability has been assigned a CVSS 4.0 score of 4.6 MEDIUM with the vector string CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U (NVD).

If the Reviewbot endpoint is deployed and accessible, attackers can bypass authentication by crafting webhook requests using the known hard-coded secret. This could allow unauthorized triggering of review actions, including posting automated comments or reviews, influencing checks, or manipulating repository signals. The primary risk affects workflow integrity rather than confidentiality or availability, though secondary effects like noisy automation, misleading reviews, or workflow disruptions are possible (GitHub Advisory).

The vulnerability has been fixed in Allstar version 4.5 and later releases. Organizations running affected versions should upgrade to v4.5 or later. Those who have not enabled or exposed the Reviewbot endpoint are not affected by this vulnerability (GitHub Advisory).