CVE-2021-25916

CRITICALNVD 9.89.8—

9.8

Prototype pollution vulnerability in 'patchmerge' versions 1.0.0 through 1.0.1 allows an attacker to cause a denial of service and may lead to remote code execution.

CVSS v3: 9.8
EG Score: 9.8(medium)
EPSS: 86.6%
KEV: Not listed

Published

March 16, 2021

Last Modified

April 30, 2025

Advisory Details (1)

Auto-updated May 26, 2026

Upstream fix merged — awaiting tagged release. Sources: github_commit.

github_commit

commit 5b383c537eae (pjshumphreys/patchmerge)

Fix landed in pjshumphreys/patchmerge commit 5b383c537eae — awaiting tagged release

https://github.com/pjshumphreys/patchmerge/commit/5b383c537eae7a00ebd26d3f7211dac99ddecb12

Affected Packages

(1 across 1 ecosystem)

npm(1)

Package	Vulnerable range	Fixed in	Dependents
patchmerge	—	1.0.2	—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

CWE-1321Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution)

Data Freshness Timeline

(refreshed 6× in last 7d / 6× in last 30d)

Every time one of our enrichment pipelines (NVD, MITRE cvelistV5, EPSS, CISA KEV, GHSA, OSV, vendor advisories) ran against this CVE. Most recent first.

2026-05-27 13:39 UTCepss_batch
2026-05-27 13:39 UTCepss_batch
2026-05-26 19:43 UTCEG score recompute
2026-05-26 13:42 UTCepss_batch
2026-05-26 07:17 UTCepss_batch
2026-05-26 07:17 UTCepss_batch

Frequently asked(5)

What is CVE-2021-25916?

CVE-2021-25916 is a critical vulnerability published on March 16, 2021. Prototype pollution vulnerability in 'patchmerge' versions 1.0.0 through 1.0.1 allows an attacker to cause a denial of service and may lead to remote code execution.

When was CVE-2021-25916 disclosed?

CVE-2021-25916 was first published in the National Vulnerability Database on March 16, 2021, with the most recent update on April 30, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2021-25916 actively exploited?

CVE-2021-25916 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 86.6% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2021-25916?

CVE-2021-25916 has a CVSS v3 base score of 9.8 (NVD).

How do I remediate CVE-2021-25916?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-25916, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2021-25916

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