CVE-2025-61926 Allstar Reviewbot has Authentication Bypass via Hard-coded Webhook Secret
Attackers can bypass webhook authentication in Allstar Reviewbot using a hard-coded secret, allowing unauthorized policy enforcement actions.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-61926?
CVE-2025-61926 is a medium-severity vulnerability in ossf allstar, published on 9 Oct 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Allstar is a GitHub App to set and enforce security policies. In versions prior to 4.5, a vulnerability in Allstar’s Reviewbot component caused inbound webhook requests to be validated against a hard-coded, shared secret. The value used for the secret token was compiled into the Allstar binary and could not be configured at runtime. In practice, this meant that every deployment using Reviewbot would validate requests with the same secret unless the operator modified source code and rebuilt the component - an expectation that is not documented and is easy to miss. All Allstar releases prior to v4.5 that include the Reviewbot code path are affected. Deployments on v4.5 and later are not affected. Those who have not enabled or exposed the Reviewbot endpoint are not exposed to this issue.
Which versions are affected by CVE-2025-61926?
3 open source packages ship an affected version, including github.com/ossf/allstar.
| Package | Affected | Fixed in |
|---|---|---|
github.com/ossf/allstar Go | All versions | 0.0.0-20250721181116-e004ecb540d6 |
github.com/ossf/allstar Go | All versions | 0.0.0-20250721181116-e004ecb540d6 |
github.com/ossf/allstar Go | All versions | 0.0.0-20250721181116-e004ecb540d6 |
How do I fix CVE-2025-61926?
Upgrade github.com/ossf/allstar to 0.0.0-20250721181116-e004ecb540d6 or later.
Is CVE-2025-61926 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-61926 exists.
Sources
Also known as GHSA-33f4-mjch-7fpr, GO-2025-4018.