Quick answers
- Is This vulnerability exploited in the wild?
- No. Junglewise Threat Intelligence has no report of This vulnerability being exploited in the wild.
- How severe is This vulnerability?
- Informational severity, published 13 October 2026.
- Which products and versions are affected?
- tokio (crates.io) SEMVER:introduced=0.3.2,fixed=1.51.6,introduced=1.52.0,fixed=1.53.3; Tokio project Tokio 0.3.2 to 1.51.5, 1.52.0 to 1.53.2.
- Is there a fix for This vulnerability?
- Yes. tokio (crates.io): upgrade to 1.53.3 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is This vulnerability attacked?
- It is attacked with local access, in a software library.
- Am I affected?
- Check whether you run tokio (crates.io) or Tokio project Tokio at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
How to fix
- tokio (crates.io): upgrade to 1.53.3 or later
cargo update -p tokio
Technical details
The issue exists in AsyncFd::new, AsyncFd::with_interest, AsyncFd::try_new, and AsyncFd::try_with_interest, which accept any T: AsRawFd without validating ownership or validity. This allows safe Rust code to construct AsyncFd from arbitrary file descriptors, and enables file descriptor use-after-free when a descriptor is closed and reused by the OS while Tokio's internal epoll/kqueue structures still hold a dangling pointer to internal allocations. The advisory deprecates these safe constructors in favor of unsafe register and register_with_interest, placing the burden on callers to ensure descriptor validity.
Affected products
- tokio project tokio 0.3.2 to 1.51.5, 1.52.0 to 1.53.2
Timeline
- 2026-10-13: disclosed
- 2026-10-23: patched