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No exploitation reportedFix available

CVE-2023-40030

No exploitation reported by the sources we read.

  • Published2023-08-24
  • Fixed in1.72
  • WeaknessCWE-79

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2023-08-2423:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2023-40030?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2023-40030?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

OSV · NVD
cargo
BranchAffectedFixed in
1.x≥ 1.60.0, < 1.721.72
Rust-lang rust
BranchAffectedFixed in
1.x≥ 1.60.0, < 1.72.01.72.0

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

  1. Update cargo to 1.72

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub

Sources

  • CISA-ADPSSVC decisionnone2024-09-30
  • OpenCVESSVC decisionnone—
  • CNACVSS 3.16.1read 2026-10-23
  • NVDCVSS 3.16.1read 2026-10-23
  • CNAweakness (CWE)CWE-79read 2026-10-23
  • FIRST EPSSEPSS score0.9 %2026-10-23
  • OSVaffected packages—

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Published
2023-08-24
Last Modified
2026-06-17
NVD status
Modified

Frequently asked questions

What is CVE-2023-40030?

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.

Is CVE-2023-40030 actively exploited?

Active exploitation of CVE-2023-40030 has not been confirmed. Its EPSS score was 0.9% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

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

CVE-2023-40030 has a CVSS v3 base score of 6.1 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

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