CVE catalog

CVE-2026-93753

deepmerge through 4.3.1 contains a prototype poisoning vulnerability in the mergeObject() function that fails to properly validate keys being written to target objects. Attackers can supply malicious

[CVE catalog]

Severity: High · CVSS 8.7CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Published: Sep 18, 2026, 5:51:37 PM UTC
Updated: Sep 18, 2026, 6:18:34 PM UTC
Source: [NVD] · [CVE record]
EPSS: 0.51% · Oct 25, 2026

deepmerge through 4.3.1 contains a prototype poisoning vulnerability in the mergeObject() function that fails to properly validate keys being written to target objects. Attackers can supply malicious source objects in merge operations to inject attacker-controlled properties into the returned object's prototype, causing applications to inherit unintended values when accessing properties without own-property checks.

Vulnerable and fixed packages

Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.

Distribution	Package	Release	Version	Status
Debian	node-deepmerge	sid	`4.3.1+~1.1.1-1`	vulnerable
Debian	node-deepmerge	forky	`4.3.1+~1.1.1-1`	vulnerable
Debian	node-deepmerge	trixie	`4.3.1+~1.1.1-1`	vulnerable
Debian	node-deepmerge	bookworm	`4.2.2+~1.1.1-3`	vulnerable

Fixed-version evidence

Distribution	Package	Type	Release	Fixed version	Urgency	Origin	Bugs
Debian	node-deepmerge	source	sid	`(unfixed)`	not yet assigned	Not reported	[1148407]
Debian	node-deepmerge	source	forky	`(unfixed)`	not yet assigned	Not reported	[1148407]
Debian	node-deepmerge	source	trixie	`(unfixed)`	not yet assigned	Not reported	[1148407]
Debian	node-deepmerge	source	bookworm	`(unfixed)`	not yet assigned	Not reported	[1148407]

[Debian bug #1148407]

Notes

[trixie] node-deepmerge: Minor issue [bookworm] node-deepmerge: Minor issue

OpenFactory catalog packages

[Debian 12 (Bookworm)]

[node-deepmerge]Affected
Details (2)
- 4.2.2+~1.1.1-3 · all · bookworm
  Affected
  nvd · node-deepmerge · debian · bookworm; nvd · node-deepmerge · debian · 12
- 4.2.2+~1.1.1-3 · all · bookworm
  Affected
  nvd · node-deepmerge · debian · bookworm; nvd · node-deepmerge · debian · 12

[Debian 13 (Trixie)]

[node-deepmerge]Affected
Details (2)
- 4.3.1+~1.1.1-1 · all · trixie
  Affected
  nvd · node-deepmerge · debian · 13
- 4.3.1+~1.1.1-1 · all · trixie
  Affected
  nvd · node-deepmerge · debian · 13

Observed: Oct 23, 2026, 8:36:54 PM UTC

References

[Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX]