CVE-2026-93753

HIGHPre-NVD 7.57.5—
EchelonGraph scoreHIGH confidence

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-09-18. a secondary CVSS source baseline 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this weekElevated
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.5Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
7.5
EG Score
7.5(high)
EG Risk
65(Attend)
EG Risk 65/100SSVC: Attend

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity75% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
0%
EPSS %ILE
30%
KEV
Not listed

Published

September 18, 2026

Last Modified

September 18, 2026

Advisory Details (4)

Auto-updated Sep 18, 2026
🔬 Proof of concept available. No patch confirmed yet.
generic

deepmerge through 4.3.1 Prototype Poisoning via mergeObject | Advisories | VulnCheck

https://www.vulncheck.com/advisories/deepmerge-through-4.3.1-prototype-poisoning-via-mergeobject
generic🟡 PoC Available

Security Advisory: Prototype-poisoning guard bypass in deepmerge lets a merged object inherit an attacker-controlled prototype · Issue #273 · TehShrike/deepmerge · GitHub

https://github.com/TehShrike/deepmerge/issues/273
generic

deepmerge/index.js at 5b87756a5671635679001cbac72aa42f23472c81 · TehShrike/deepmerge · GitHub

https://github.com/TehShrike/deepmerge/blob/5b87756a5671635679001cbac72aa42f23472c81/index.js#L39-L60
generic

GitHub - TehShrike/deepmerge: A library for deep (recursive) merging of Javascript objects · GitHub

https://github.com/TehShrike/deepmerge

Vendor Advisories for CVE-2026-93753(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 10× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-09-19 20:32 UTCEG score recompute
  2. 2026-09-19 20:32 UTCGHSA enrichment
  3. 2026-09-19 08:31 UTCGHSA enrichment
  4. 2026-09-18 20:31 UTCEG score recompute
  5. 2026-09-18 20:31 UTCGHSA enrichment
  6. 2026-09-18 19:19 UTCEG score recompute
  7. 2026-09-18 19:19 UTCGHSA enrichment
  8. 2026-09-18 18:27 UTCEG score recompute
  9. 2026-09-18 17:54 UTCEG score recompute
  10. 2026-09-18 17:54 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-93753?
CVE-2026-93753 is a high vulnerability published on September 18, 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…
When was CVE-2026-93753 disclosed?
CVE-2026-93753 was first published in the National Vulnerability Database on September 18, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-93753 actively exploited?
CVE-2026-93753 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 70.0% of all scored CVEs.
What is the CVSS score of CVE-2026-93753?
CVE-2026-93753 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-93753?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-93753, 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

Explore the affected products and dependency analysis for CVE-2026-93753

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