RUSTSEC-2021-0072 CVE-2021-38191 GHSA-2grh-hm3w-w7hv
Task dropped in wrong thread when aborting `LocalSet` task
- Severity
- 5.9 / 10
- Medium · CVSS 3.1
- Exploit chance (EPSS)
- 0.83%
- Chance of exploitation in the next 30 days. Higher than 57.67% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
- CWE-366 Race Condition within a Thread
- Fix
1.8.1- Upgrade tokio to this version or later
Description
When aborting a task with JoinHandle::abort, the future is dropped in the
thread calling abort if the task is not currently being executed. This is
incorrect for tasks spawned on a LocalSet.
This can easily result in race conditions as many projects use Rc or RefCell
in their Tokio tasks for better performance.
See tokio#3929 for more details.
Affected versions
crates.io
| Package | Vulnerable | Fixed in |
|---|---|---|
| tokio | >= 1.8.0, < 1.8.1 |
1.8.1 |
| tokio | >= 1.7.0, < 1.7.2 |
1.7.2 |
| tokio | >= 1.6.0, < 1.6.3 |
1.6.3 |
| tokio | >= 0.3.0, < 1.5.1 |
1.5.1 |
| tokio | >= 0.3.0, < 1.5.1>= 1.6.0, < 1.6.3>= 1.7.0, < 1.7.2>= 1.8.0, < 1.8.1 |
1.5.11.6.31.7.21.8.1 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
tokio crates.io → 1.8.1
- cargo
cargo update -p tokio --precise 1.8.1
Severity breakdown
CVSS 3.1 5.9
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Weakness
CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.
How to prevent it
- Architecture and Design: In languages that support it, use synchronization primitives. Only wrap these around critical code to minimize the impact on performance.
- Architecture and Design: Use thread-safe capabilities such as the data access abstraction in Spring.
- Architecture and Design: Minimize the usage of shared resources in order to remove as much complexity as possible from the control flow and to reduce the likelihood of unexpected conditions occurring. Additionally, this will minimize the amount of synchronization necessary and may even help to reduce the likelihood of a denial of service where an attacker may be able to repeatedly trigger a critical section (CWE-400).
- Implementation: When using multithreading and operating on shared variables, only use thread-safe functions.
- Implementation: Use atomic operations on shared variables. Be wary of innocent-looking constructs such as "x++". This may appear atomic at the code layer, but it is actually non-atomic at the instruction layer, since it involves a read, followed by a computation, followed by a write.
- Implementation: Use a mutex if available, but be sure to avoid related weaknesses such as CWE-412.
- Implementation: Avoid double-checked locking (CWE-609) and other implementation errors that arise when trying to avoid the overhead of synchronization.
- Implementation: Disable interrupts or signals over critical parts of the code, but also make sure that the code does not go into a large or infinite loop.
- Implementation: Use the volatile type modifier for critical variables to avoid unexpected compiler optimization or reordering. This does not necessarily solve the synchronization problem, but it can help.
- Architecture and Design, Operation: Run your code using the lowest privileges that are required to accomplish the necessary tasks [REF-76]. If possible, create isolated accounts with limited privileges that are only used for a single task. That way, a successful attack will not immediately give the attacker access to the rest of the software or its environment. For example, database applications rarely need to run as the database administrator, especially in day-to-day operations.
CWE-366: Race Condition within a Thread
If two threads of execution use a resource simultaneously, there exists the possibility that resources may be used while invalid, in turn making the state of execution undefined.
How to prevent it
- Architecture and Design: Use locking functionality. This is the recommended solution. Implement some form of locking mechanism around code which alters or reads persistent data in a multithreaded environment.
- Architecture and Design: Create resource-locking validation checks. If no inherent locking mechanisms exist, use flags and signals to enforce your own blocking scheme when resources are being used by other threads of execution.
References
Advisories
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-5wjr-9356-4wc8 Tokio: Race condition in `tokio::time::Interval` | Medium | Also affects tokio |
| RUSTSEC-2026-0386 `AsyncFd::new` and related constructors violate I/O safety | Not rated yet | Also affects tokio |
| GHSA-rr8g-9fpq-6wmg Tokio broadcast channel calls clone in parallel, but does not require `Sync` | Low | Also affects tokio |
| GHSA-4q83-7cq4-p6wg `tokio::io::ReadHalf<T>::unsplit` is Unsound | Low | Also affects tokio |
| GHSA-7rrj-xr53-82p7 Tokio reject_remote_clients configuration may get dropped when creating a Windows named pipe | Medium | Also affects tokio |
| RUSTSEC-2021-0124 Race Condition in tokio | High | Also affects tokio |
| GHSA-44jh-23m7-hpcf @better-auth/drizzle-adapter: Concurrent requests can exceed rate limits on PostgreSQL | Medium | Same weakness, CWE-362 |
| GHSA-494h-xx7x-5frh Microsoft Security Advisory CVE-2026-70183 - ASP.NET Core Security Feature Bypass Vulnerability | High | Same weakness, CWE-362 |
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