CVE-2025-8129: A vulnerability, which was classified as problematic, was found in KoaJS Koa up to 3.0.0

Q: How do I fix CVE-2025-8129?

koa: upgrade to 2.16.2. Exact commands for each OS are on this page.

Q: Is CVE-2025-8129 being exploited?

CVE-2025-8129 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-2025-8129 affect?

CVE-2025-8129 affects koa. Severity is low (CVSS 3.5). A vulnerability, which was classified as problematic, was found in KoaJS Koa up to 3.0.0. Affected is the function back in the library lib/response.js of the component HTTP Header Handler. The manipulation of the argument Referrer leads to

Q: How urgent is CVE-2025-8129?

Priority 22/100. Public exploit reference

Routine

LOW 3.5UPGRADE

CVE-2025-8129 is a low-severity flaw (CVSS 3.5) affecting koa. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A vulnerability, which was classified as problematic, was found in KoaJS Koa up to 3.0.0. Affected is the function back in the library lib/response.js of the component HTTP Header Handler. The manipulation of the argument Referrer leads to open redirect. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used.

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	3.5 (Low)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	Required
EPSS exploit chance	0.3% (top 79%)
CISA exploited list	No
Weakness	CWE-601
Published	2025-07-25
Last modified	2026-06-17

Publisher (CNA): VulDB · Vendor: koajs

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2025-07-25 05:15 UTCPublished CVE record published
2026-06-17 10:06 UTCUpdated Record last modified

koajs koa UPGRADE

Affected: >= 2.0.0 and < 2.16.2 · 3.0.0 · 3.0.0 alpha0 · 3.0.0 alpha1 · 3.0.0 alpha2 · 3.0.0 alpha3 · 3.0.0 alpha4 · 3.0.0 alpha5

Fixed in: 2.16.2

Safe to downgrade to: a release before 2.0.0

1. Check installed version

npm ls koa

2. UPGRADE to 2.16.2

npm install koa@">=2.16.2"

3. If no update is available yet, DOWNGRADE to a release before 2.0.0

npm view koa versions npm install koa@"<2.0.0"

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-2025-8129?

koa: upgrade to 2.16.2. Exact commands for each OS are on this page.

Is CVE-2025-8129 being exploited?

CVE-2025-8129 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-2025-8129 affect?

CVE-2025-8129 affects koa. Severity is low (CVSS 3.5). A vulnerability, which was classified as problematic, was found in KoaJS Koa up to 3.0.0. Affected is the function back in the library lib/response.js of the component HTTP Header Handler. The manipulation of the argument Referrer leads to

How urgent is CVE-2025-8129?

Priority 22/100. Public exploit reference

Related CVEs

CVE-2025-62595 MEDIUM 4.3 UPGRADE Koa is expressive middleware for Node.js using ES2017 async functions
CVE-2026-27959 HIGH 7.5 UPGRADE Koa is middleware for Node.js using ES2017 async functions
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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