CVE-2025-62595: Koa is expressive middleware for Node.js using ES2017 async functions

Q: How do I fix CVE-2025-62595?

koa: upgrade to 3.0.3. Exact commands for each OS are on this page.

Q: Is CVE-2025-62595 being exploited?

CVE-2025-62595 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2025-62595 affect?

CVE-2025-62595 affects koa. Severity is medium (CVSS 4.3). Koa is expressive middleware for Node.js using ES2017 async functions. In versions 2.16.2 to before 2.16.3 and 3.0.1 to before 3.0.3, a bypass to CVE-2025-8129 was discovered in the Koa.js framework affecting its back redirect functionality

Q: How urgent is CVE-2025-62595?

Priority 26/100. Public exploit reference

Routine

MEDIUM 4.3UPGRADE

CVE-2025-62595 is a medium-severity flaw (CVSS 4.3) affecting koa. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Koa is expressive middleware for Node.js using ES2017 async functions. In versions 2.16.2 to before 2.16.3 and 3.0.1 to before 3.0.3, a bypass to CVE-2025-8129 was discovered in the Koa.js framework affecting its back redirect functionality. In certain circumstances, an attacker can manipulate the Referer header to force a user’s browser to navigate to an external, potentially malicious website. This occurs because the implementation incorrectly

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	4.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.3% (top 78%)
CISA exploited list	No
Weakness	CWE-601
Published	2025-10-21
Last modified	2026-10-08

Publisher (CNA): GitHub, Inc. · Vendor: koajs

Last updated 2026-10-08 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2025-10-21 17:15 UTCPublished CVE record published
2026-10-08 11:10 UTCUpdated Record last modified

koajs koa UPGRADE

Affected: >= 3.0.1 and < 3.0.3 · 2.16.2

Fixed in: 3.0.3

Safe to downgrade to: a release before 2.16.2

1. Check installed version

npm ls koa

2. UPGRADE to 3.0.3

npm install koa@">=3.0.3"

3. If no update is available yet, DOWNGRADE to a release before 2.16.2

npm view koa versions npm install koa@"<2.16.2"

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2025-62595?

koa: upgrade to 3.0.3. Exact commands for each OS are on this page.

Is CVE-2025-62595 being exploited?

CVE-2025-62595 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2025-62595 affect?

CVE-2025-62595 affects koa. Severity is medium (CVSS 4.3). Koa is expressive middleware for Node.js using ES2017 async functions. In versions 2.16.2 to before 2.16.3 and 3.0.1 to before 3.0.3, a bypass to CVE-2025-8129 was discovered in the Koa.js framework affecting its back redirect functionality

How urgent is CVE-2025-62595?

Priority 26/100. Public exploit reference

Software pages

Node.js vulnerabilities

Related CVEs

CVE-2026-27959 HIGH 7.5 UPGRADE Koa is middleware for Node.js using ES2017 async functions
CVE-2025-8129 LOW 3.5 UPGRADE A vulnerability, which was classified as problematic, was found in KoaJS Koa up to 3.0.0
CVE-2025-32379 MEDIUM 5.0 UPGRADE Koa is expressive middleware for Node.js using ES2017 async functions
CVE-2025-25200 HIGH 7.5 UPGRADE Koa is expressive middleware for Node.js using ES2017 async functions

References

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