CVE-2026-93753 (GCVE-0-2026-93753)
Vulnerability from cvelistv5 – Published: 2026-09-18 17:51 – Updated: 2026-09-18 19:17
VLAI
EPSS
VEX
Title
deepmerge through 4.3.1 Prototype Poisoning via mergeObject
Summary
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.
Severity
SSVC
Exploitation: poc
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-18 19:16 UTC
CWE
- CWE-1321 - Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
Assigner
References
4 references
| URL | Tags |
|---|---|
| https://github.com/TehShrike/deepmerge/issues/273 | issue-tracking |
| https://github.com/TehShrike/deepmerge | product |
| https://github.com/TehShrike/deepmerge/blob/5b877… | technical-description |
| https://www.vulncheck.com/advisories/deepmerge-th… | third-party-advisory |
Impacted products
Date Public
2026-09-17 00:00
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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