GHSA-wmfg-55f9-j8hq is a critical-severity (CVSS 10) CWE-74 vulnerability in com.browserup:browserup-proxy. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether GHSA-wmfg-55f9-j8hq is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Server-Side Template Injection
Real-World Exposure
com.browserup:browserup-proxyReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
Description
Impact
A Server-Side Template Injection was identified in BrowserUp Proxy enabling attackers to inject arbitrary Java EL expressions, leading to unauthenticated Remote Code Execution (RCE) vulnerability. This has been assigned CVE-2020-26282.
Patches
Effective Immediately, all users should upgrade to version 2.1.2 or higher.
Workarounds
None.
References
https://securitylab.github.com/research/bean-validation-RCE
For more information
If you have any questions or comments about this advisory:
- Open an issue in the BrowserUp Proxy repo
- Contact us via the BrowserUp website or email us at [email protected]
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | com.browserup:browserup-proxy | all versions | 2.1.2 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for com.browserup:browserup-proxy. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update com.browserup:browserup-proxy to 2.1.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-wmfg-55f9-j8hq 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 pinpoints whether GHSA-wmfg-55f9-j8hq is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-wmfg-55f9-j8hq. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-wmfg-55f9-j8hq in your dependencies?
O3 detects GHSA-wmfg-55f9-j8hq across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.