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ReDoS Vulnerability in ua-parser-js version

High severity GitHub Reviewed Published Jan 23, 2023 in faisalman/ua-parser-js • Updated Oct 17, 2025

Package

npm ua-parser-js (npm)

Affected versions

>= 0.8.0, < 1.0.33
>= 0.7.30, < 0.7.33

Patched versions

1.0.33
0.7.33

Description

Description:

A regular expression denial of service (ReDoS) vulnerability has been discovered in ua-parser-js.

Impact:

This vulnerability bypass the library's MAX_LENGTH input limit prevention. By crafting a very-very-long user-agent string with specific pattern, an attacker can turn the script to get stuck processing for a very long time which results in a denial of service (DoS) condition.

Affected Versions:

From version 0.7.30 to before versions 0.7.33 / 1.0.33.

Patches:

A patch has been released to remove the vulnerable regular expression, update to version 0.7.33 / 1.0.33 or later.

References:

Regular expression Denial of Service - ReDoS

Credits:

Thanks to @snyk who first reported the issue.

References

@faisalman faisalman published to faisalman/ua-parser-js Jan 23, 2023
Published to the GitHub Advisory Database Jan 24, 2023
Reviewed Jan 24, 2023
Published by the National Vulnerability Database Jan 26, 2023
Last updated Oct 17, 2025

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(80th percentile)

Weaknesses

Uncontrolled Resource Consumption

The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources. Learn more on MITRE.

Inefficient Regular Expression Complexity

The product uses a regular expression with an inefficient, possibly exponential worst-case computational complexity that consumes excessive CPU cycles. Learn more on MITRE.

CVE ID

CVE-2022-25927

GHSA ID

GHSA-fhg7-m89q-25r3

Source code

Credits

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