CVE-2026-3449 — @tootallnate/once
Fix: TooTallNate/once@b9f43ccCVE-2026-3449 is a CWE-705 vulnerability in @tootallnate/once. A fix is available for @tootallnate/once — see the affected versions and patch details below.
@tootallnate/once vulnerable to Incorrect Control Flow Scoping
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.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-3449.
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
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
@tootallnate/oncenpmDescription
Versions of the package @tootallnate/once before 3.0.1 are vulnerable to Incorrect Control Flow Scoping in promise resolving when AbortSignal option is used. The Promise remains in a permanently pending state after the signal is aborted, causing any await or .then() usage to hang indefinitely. This can cause a control-flow leak that can lead to stalled requests, blocked workers, or degraded application availability.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @tootallnate/once | ≥ 3.0.0&&< 3.0.1 | 3.0.1npm install @tootallnate/once@3.0.1 |
| 📦npm | @tootallnate/once | all versions | 2.0.1npm install @tootallnate/once@2.0.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @tootallnate/once, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @tootallnate/once to 3.0.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-3449 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-2026-3449 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-3449. 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-2026-3449 in your dependencies?
O3 Security finds CVE-2026-3449 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.