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Koajs vulnerable to Cross-Site Scripting (XSS) at ctx.redirect() function

Moderate severity GitHub Reviewed Published Apr 8, 2025 in koajs/koa • Updated Apr 9, 2025

Package

npm koa (npm)

Affected versions

< 2.16.1
>= 3.0.0-alpha.1, < 3.0.0-alpha.5

Patched versions

2.16.1
3.0.0-alpha.5

Description

Summary

In koa < 2.16.1 and < 3.0.0-alpha.5, passing untrusted user input to ctx.redirect() even after sanitizing it, may execute javascript code on the user who use the app.

Patches

This issue is patched in 2.16.1 and 3.0.0-alpha.5.

PoC

Coming soon...

Impact

  1. Redirect user to another phishing site
  2. Make request to another endpoint of the application based on user's cookie
  3. Steal user's cookie

References

@fengmk2 fengmk2 published to koajs/koa Apr 8, 2025
Published to the GitHub Advisory Database Apr 9, 2025
Reviewed Apr 9, 2025
Published by the National Vulnerability Database Apr 9, 2025
Last updated Apr 9, 2025

Severity

Moderate

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
High
Privileges required
None
User interaction
Required
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
Low

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:H/PR:N/UI:R/S:U/C:L/I:L/A:L

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.
(9th percentile)

Weaknesses

CVE ID

CVE-2025-32379

GHSA ID

GHSA-x2rg-q646-7m2v

Source code

Credits

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