CVE-2025-61926 — allstar
Fix: ossf/allstar@e004ecbCVE-2025-61926 is a CWE-453 vulnerability in github.com/ossf/allstar. A fix is available for github.com/ossf/allstar — see the affected versions and patch details below.
Allstar Reviewbot has Authentication Bypass via Hard-coded Webhook Secret
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-61926.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
github.com/ossf/allstarReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
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. While Reviewbot is not commonly enabled in standard Allstar setups, we are issuing this advisory to reach any environments where it may have been deployed.
Affected Versions
All Allstar releases prior to v4.5 that include the Reviewbot code path are affected. Deployments on v4.5 and later are not affected. If you have not enabled or exposed the Reviewbot endpoint, this issue does not apply to your installation.
Impact
If the Reviewbot endpoint is deployed and reachable, an attacker can bypass authentication by crafting webhook requests that use the known, hard-coded secret. Because signature verification will succeed, Reviewbot would treat these requests as authentic when they should be rejected. Depending on the permissions and automations attached to your deployment, this could allow unauthorized triggering of review actions such as posting automated comments or reviews, influencing checks, or otherwise manipulating repository signals. The primary risk is to the integrity of repository workflows rather than confidentiality or availability, although secondary effects (e.g., noisy automation, misleading reviews, or workflow disruptions) are possible.
Exploitability
Exploiting this is straightforward and does not require an attacker to be authenticated. Anyone who can send requests to the Reviewbot webhook can reach the vulnerable code.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/ossf/allstar | all versions | 0.0.0-20250721181116-e004ecb540d6go get github.com/ossf/allstar@v0.0.0-20250721181116-e004ecb540d6 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/ossf/allstar, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/ossf/allstar to 0.0.0-20250721181116-e004ecb540d6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-61926 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2025-61926 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2025-61926. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2025-61926 in your dependencies?
O3 Security finds CVE-2025-61926 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.