CVE-2021-23397: All versions of package @ianwalter/merge are vulnerable to Prototype Pollution via the main (merge) function

This week

MEDIUM 5.6REMOTEMITIGATE

CVE-2021-23397 is a medium-severity flaw (CVSS 5.6) affecting merge. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

All versions of package @ianwalter/merge are vulnerable to Prototype Pollution via the main (merge) function. Maintainer suggests using @generates/merger instead.

Why this priority

Public exploit reference
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	5.6 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	0.8% (top 43%)
CISA exploited list	No
Weakness	CWE-1321
Published	2022-07-25
Last modified	2026-06-17

Publisher (CNA): Snyk · Vendor: merge project

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

Am I affected?

Timeline

2022-07-25 14:15 UTCPublished CVE record published
2026-06-17 03:38 UTCUpdated Record last modified

merge project merge MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

npm ls merge

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

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-2021-23397?

merge: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-23397 being exploited?

CVE-2021-23397 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-2021-23397 affect?

CVE-2021-23397 affects merge. Severity is medium (CVSS 5.6). All versions of package @ianwalter/merge are vulnerable to Prototype Pollution via the main (merge) function. Maintainer suggests using @generates/merger instead.

How urgent is CVE-2021-23397?

Priority 44/100. Public exploit reference; Remotely exploitable, no login, no user action

Related CVEs

CVE-2021-3645 CRITICAL 9.8 UPGRADE merge is vulnerable to Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution
CVE-2020-28499 HIGH 7.3 UPGRADE All versions of package merge are vulnerable to Prototype Pollution via _recursiveMerge .

References

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