CVE-2021-29452: a12n-server is an npm package which aims to provide a simple authentication system

Q: How do I fix CVE-2021-29452?

a12n-server: upgrade to 0.18.2. Exact commands for each OS are on this page.

Q: Is CVE-2021-29452 being exploited?

CVE-2021-29452 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-2021-29452 affect?

CVE-2021-29452 affects a12n-server. Severity is high (CVSS 8.1). a12n-server is an npm package which aims to provide a simple authentication system. A new HAL-Form was added to allow editing users in version 0.18.0. This feature should only have been accessible to admins. Unfortunately, privileges were i

This month

HIGH 8.1UPGRADE

CVE-2021-29452 is a high-severity flaw (CVSS 8.1) affecting a12n-server. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

a12n-server is an npm package which aims to provide a simple authentication system. A new HAL-Form was added to allow editing users in version 0.18.0. This feature should only have been accessible to admins. Unfortunately, privileges were incorrectly checked allowing any logged in user to make this change. Patched in v0.18.2.

Why this priority

High severity

A fixed release or distro patch exists.

Risk facts

CVSS score	8.1 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.8% (top 44%)
CISA exploited list	No
Weakness	CWE-269, CWE-863
Published	2021-04-16
Last modified	2026-06-17

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

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

Am I affected?

Timeline

2021-04-16 22:15 UTCPublished CVE record published
2026-06-17 03:47 UTCUpdated Record last modified

curveballjs a12n-server UPGRADE

Affected: >= 0.18.0 and < 0.18.2

Fixed in: 0.18.2

Safe to downgrade to: a release before 0.18.0

1. Check installed version

npm ls a12n-server

2. UPGRADE to 0.18.2

npm install a12n-server@">=0.18.2"

3. If no update is available yet, DOWNGRADE to a release before 0.18.0

npm view a12n-server versions npm install a12n-server@"<0.18.0"

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-2021-29452?

a12n-server: upgrade to 0.18.2. Exact commands for each OS are on this page.

Is CVE-2021-29452 being exploited?

CVE-2021-29452 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-2021-29452 affect?

CVE-2021-29452 affects a12n-server. Severity is high (CVSS 8.1). a12n-server is an npm package which aims to provide a simple authentication system. A new HAL-Form was added to allow editing users in version 0.18.0. This feature should only have been accessible to admins. Unfortunately, privileges were i

How urgent is CVE-2021-29452?

Priority 42/100. High severity

Software pages

npm packages vulnerabilities

References

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