How severe is CVE-2023-40030?

CVE-2023-40030 has a CVSS score of 6.1/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2023-40030?

CVE-2023-40030 affects the following packages: cargo (crates.io). Ecosystems affected: crates.io.

How do I fix CVE-2023-40030?

Update cargo to 1.72 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-40030 is resolved across your whole dependency graph.

How do I detect CVE-2023-40030 in my crates.io dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for cargo. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2023-40030 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2023-40030?

O3 pinpoints whether CVE-2023-40030 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2023-40030 actively exploited in the wild?

No public exploit code has been indexed for CVE-2023-40030 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2023-40030?

CVE-2023-40030 has an EPSS (Exploit Prediction Scoring System) score of 0.8%, placing it in the 53th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

When was CVE-2023-40030 published, and has it been updated?

CVE-2023-40030 was published on August 24, 2023 and was last updated on April 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🦀 crates.io

CVE-2023-40030

MEDIUM

Malicious dependencies can inject arbitrary JavaScript into cargo-generated timing reports

Also known asGHSA-wrrj-h57r-vx9p

Published

Aug 24, 2023

Updated

Apr 10, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

EPSS Exploitation Probability

via FIRST.org ↗

0.8%probability of exploitation in next 30 days

Lower Risk53th percentile+0.65%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

1 pkg affected

🦀cargo

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

Cargo downloads a Rust project’s dependencies and compiles the project. Starting in Rust 1.60.0 and prior to 1.72, Cargo did not escape Cargo feature names when including them in the report generated by cargo build --timings. A malicious package included as a dependency may inject nearly arbitrary HTML here, potentially leading to cross-site scripting if the report is subsequently uploaded somewhere. The vulnerability affects users relying on dependencies from git, local paths, or alternative registries. Users who solely depend on crates.io are unaffected.

Rust 1.60.0 introduced cargo build --timings, which produces a report of how long the different steps of the build process took. It includes lists of Cargo features for each crate. Prior to Rust 1.72, Cargo feature names were allowed to contain almost any characters (with some exceptions as used by the feature syntax), but it would produce a future incompatibility warning about them since Rust 1.49. crates.io is far more stringent about what it considers a valid feature name and has not allowed such feature names. As the feature names were included unescaped in the timings report, they could be used to inject Javascript into the page, for example with a feature name like features = ["<img src='' onerror=alert(0)"]. If this report were subsequently uploaded to a domain that uses credentials, the injected Javascript could access resources from the website visitor.

This issue was fixed in Rust 1.72 by turning the future incompatibility warning into an error. Users should still exercise care in which package they download, by only including trusted dependencies in their projects. Please note that even with these vulnerabilities fixed, by design Cargo allows arbitrary code execution at build time thanks to build scripts and procedural macros: a malicious dependency will be able to cause damage regardless of these vulnerabilities. crates.io has server-side checks preventing this attack, and there are no packages on crates.io exploiting these vulnerabilities. crates.io users still need to excercise care in choosing their dependencies though, as remote code execution is allowed by design there as well.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🦀crates.io	`cargo`	≥ 1.60.0&&< 1.72	1.72

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for cargo. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update cargo to 1.72 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-40030 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2023-40030 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2023-40030. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

Cargo downloads a Rust project’s dependencies and compiles the project. Starting in Rust 1.60.0 and prior to 1.72, Cargo did not escape Cargo feature names when including them in the report generated by `cargo build --timings`. A malicious package included as a dependency may inject nearly arbitrary HTML here, potentially leading to cross-site scripting if the report is subsequently uploaded somewhere. The vulnerability affects users relying on dependencies from git, local paths, or alternative registries. Users who solely depend on crates.io are unaffected. Rust 1.60.0 introduced `cargo buil

O3 Security · Impact-Aware SCA

Is CVE-2023-40030 in your dependencies?

O3 detects CVE-2023-40030 across crates.io dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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