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Fencer Vulns
medium 6.1

CVE-2023-40030 json

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

published 2023-08-24 3 y ago modified 2026-09-10 1 mo ago also GHSA-wrrj-h57r-vx9p , EUVD-2023-2375

cvss
6.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.9%
EPSS 0.9% chance of exploitation in 30 days, percentile 59%
public exploits
0
none known

Summary

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.

Patch / fix

  • crates.io cargo 1.72
  • rust-lang rust 1.72.0
  • rust-cargo Debian 14, Debian 13 0.76.0-1

debian advisories DEBIAN-CVE-2023-40030

  • rustc Ubuntu 24.04 LTS 1.73.0+dfsg0ubuntu1-0ubuntu1

ubuntu advisories UBUNTU-CVE-2023-40030

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • rust1.72 SLE Module for Development Tools 15 SP5, SLE Module for Development Tools 15 SP4, openSUSE Leap 15.5 +1 more 1.72.0-150400.9.3.1
  • rust SLE Module for Development Tools 15 SP5, SLE Module for Development Tools 15 SP4, openSUSE Leap 15.5 +1 more 1.72.0-150400.24.24.1

suse advisories SUSE-SU-2023:3722-1

  • rust1.72 openSUSE Tumbleweed 1.72.1-1.1

opensuse advisories openSUSE-SU-2024:13262-1

  • rust CBL-Mariner 2.0 1.72.0-2

azure linux advisories AZL-28511

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2023-40030 updated cvss 6.1

rust-cargo: XSS via dependency HTML injection

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.90% chance of exploitation in the next 30 days, higher than 59% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
NVD 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
crates.io cargo
>=1.60.0, <1.72
1.72

Affected products

  • rust-lang cargo

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

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.