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MEDIUM severity

CVE-2023-6180 — tokio-boring

MEDIUMFix: cloudflare/boring@a327833

CVE-2023-6180 is a medium-severity (CVSS 5.3) Uncontrolled Resource Consumption vulnerability in tokio-boring. A fix is available for tokio-boring — see the affected versions and patch details below.

Resource exhaustion via memory leak in tokio-boring

Also known asGHSA-pjrj-h4fg-6gm4
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Nov 4, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
0.6%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs50th percentile — riskier than 50% of all scored CVEsHighest risk
0.00%0.37%0.75%1.12%0.1%0.6%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected
🦀tokio-boring

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.

Description

Impact

The tokio-boring library in version 4.0.0 is affected by a memory leak issue that can lead to excessive resource consumption and potential DoS by resource exhaustion. The set_ex_data function used by the library did not deallocate memory used by pre-existing data in memory each time after completing a TLS connection causing the program to consume more resources with each new connection.

Patches

The issue is fixed in version 4.1.0 of tokio-boring.

References

CVE-2023-6180 at cve.org

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🦀crates.iotokio-boring≥ 4.0.0&&< 4.1.04.1.0cargo update -p tokio-boring --precise 4.1.0

Affected Products

1 product · 1 configurations
Application
boringcloudflare
1 version
4.0.0

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for tokio-boring, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update tokio-boring to 4.1.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-6180 is resolved across your whole dependency graph.

  3. Workarounds

    Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Frequently Asked Questions

### Impact The tokio-boring library in version 4.0.0 is affected by a memory leak issue that can lead to excessive resource consumption and potential DoS by resource exhaustion. The `set_ex_data` function used by the library did not deallocate memory used by pre-existing data in memory each time after completing a TLS connection causing the program to consume more resources with each new connection. ### Patches The issue is fixed in version 4.1.0 of tokio-boring. ### References [CVE-2023-6180 at cve.org](https://www.cve.org/CVERecord?id=CVE-2023-6180)
O3 Security · Impact-Aware SCA

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CVE-2023-6180: tokio-boring DoS — Fixed in 4.1.0