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Fencer Vulns
medium 5.9

CVE-2021-38191 json

Race condition in tokio

published 2021-07-07 5 y ago modified 2026-06-17 4 mo ago also GHSA-2grh-hm3w-w7hv , RUSTSEC-2021-0072 , EUVD-2021-1512

cvss
5.9
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.8%
EPSS 0.8% chance of exploitation in 30 days, percentile 57%
public exploits
0
none known

Summary

An issue was discovered in the tokio crate before 1.8.1 for Rust. Upon a JoinHandle::abort, a Task may be dropped in the wrong thread.

Patch / fix

  • crates.io tokio 1.5.1, 1.6.3, 1.7.2, 1.8.1
  • tokio tokio 1.5.1, 1.6.3, 1.7.2

Exploit prediction

0.83% chance of exploitation in the next 30 days, higher than 57% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • rustsec.org https://rustsec.org/advisories/RUSTSEC-2021-0072.html referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:N/I:N/A:P
GitHub 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
crates.io tokio
>=1.8.0, <1.8.1
>=1.7.0, <1.7.2
>=1.6.0, <1.6.3
>=0.3.0, <1.5.1
1.8.1
1.7.2
1.6.3
1.5.1

Classification

Weakness
  • CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization
  • CWE-366 Race Condition within a Thread

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.