CVE-2026-3449 @tootallnate/once vulnerable to Incorrect Control Flow Scoping
An attacker can cause indefinite hangs in applications using this library with AbortSignal, leading to stalled requests and degraded availability.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-3449?
CVE-2026-3449 is a medium-severity denial of service vulnerability in @tootallnate/once, published on 3 Mar 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
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.
Weakness: CWE-705
Which versions are affected by CVE-2026-3449?
4 open source packages ship an affected version, including @tootallnate/once.
| Package | Affected | Fixed in |
|---|---|---|
@tootallnate/once npm | All versions | 2.0.1 |
@tootallnate/once npm | All versions | 2.0.1 |
@tootallnate/once npm | From 3.0.0 | 3.0.1 |
@tootallnate/once npm | From 3.0.0 | 3.0.1 |
Linux distribution packages (2)
heroic-games-launcher openSUSE:Tumbleweed | All versions | 2.20.1-2.1 |
python-jupyterlab-templates openSUSE:Tumbleweed | All versions | 0.5.2-4.1 |
How do I fix CVE-2026-3449?
Upgrade @tootallnate/once to a fixed version for your release line: 2.0.1 or 3.0.1.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-3449 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-3449 exists.
Sources
Also known as CLEANSTART-2026-JL75722, CLEANSTART-2026-RV70220, CLSA-2026-1792142145, ECHO-318f-4145-6b35, GHSA-vpq2-c234-7xj6, MINI-28xx-62cv-h8g7 and 34 more.