Summary
Tokio: Race condition in tokio::time::Interval
On the multi-threaded runtime, there is a race condition between Interval::poll_tick and the runtime's time driver.
This affects Interval only. Sleep and Timeout are not affected.
Details
In Tokio v1.54.0, a race condition between tokio::time::Interval::poll_tick (including .tick().await) and the runtime time driver can drop an internal timer entry without synchronizing with the driver thread that is firing it. This causes a data race and use-after-free on the timer's waker and task state in safe Rust, leading to assertion panics, task reference-count corruption, or heap memory corruption.
This bug was introduced by https://github.com/tokio-rs/tokio/pull/8458, and it was fixed by https://github.com/tokio-rs/tokio/pull/8692.
Credits
Thank you to creepycode and carabistouille for reporting this privately using the procedure outlined in our security policy. They both reported the issue independently of each other.
Impact
This may lead to crashes and use-after-frees in applications using Interval on a multi-threaded runtime.
Since this issue is known to lead to crashes in production systems, the v1.54.0 release of Tokio has been yanked.
Multiple concurrent operations access a shared resource without proper synchronization, producing unpredictable results depending on timing. Typical impact: TOCTOU exploits, data corruption, or privilege escalation.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2026-115567? CVE-2026-115567 is a medium-severity race condition vulnerability in tokio (rust), affecting versions = 1.54.0. It is fixed in 1.54.1. Multiple concurrent operations access a shared resource without proper synchronization, producing unpredictable results depending on timing.
- Which versions of tokio are affected by CVE-2026-115567? tokio (rust) versions = 1.54.0 is affected.
- Is there a fix for CVE-2026-115567? Yes. CVE-2026-115567 is fixed in 1.54.1. Upgrade to this version or later.
- Is CVE-2026-115567 exploitable, and should I be worried? Whether CVE-2026-115567 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-115567 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-115567? Upgrade
tokioto 1.54.1 or later.