CVE-2021-26707
CVE-2021-26707 is a critical-severity vulnerability in Merge-deep Project Merge-deep with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-1321.
Key facts
- Severity: Critical (CVSS 3.x base score 9.8)
- CVSS v2: 7.5
- EPSS exploit prediction: 2% (77th percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-1321
- Affected product: Merge-deep Project Merge-deep
- Published:
- Last modified:
Description
The merge-deep library before 3.0.3 for Node.js can be tricked into overwriting properties of Object.prototype or adding new properties to it. These properties are then inherited by every object in the program, thus facilitating prototype-pollution attacks against applications using this library.
Frequently asked questions
- What is CVE-2021-26707?
- The merge-deep library before 3.0.3 for Node.js can be tricked into overwriting properties of Object.prototype or adding new properties to it. These properties are then inherited by every object in the program, thus facilitating prototype-pollution attacks against applications using this library.
- How severe is CVE-2021-26707?
- CVE-2021-26707 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2021-26707 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (77th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2021-26707?
- CVE-2021-26707 primarily affects Merge-deep Project Merge-deep. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
- How do I fix CVE-2021-26707?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
- When was CVE-2021-26707 published?
- CVE-2021-26707 was published on 2021-06-02 and last updated on 2026-06-17.
References
- https://github.com/jonschlinkert/merge-deep/commit/11e5dd56de8a6aed0b1ed022089dbce6968d82a5
- https://security.netapp.com/advisory/ntap-20210716-0008/
- https://securitylab.github.com/advisories/GHSL-2020-160-merge-deep/
- https://www.npmjs.com/package/merge-deep
Affected products (2)
- cpe:2.3:a:merge-deep_project:merge-deep:*:*:*:*:*:node.js:*:*
- cpe:2.3:a:netapp:e-series_performance_analyzer:-:*:*:*:*:*:*:*
More vulnerabilities in Merge-deep Project Merge-deep
- CVE-2018-3722 — High (CVSS 8.8): merge-deep node module before 3.0.1 suffers from a Modification of Assumed-Immutable Data (MAID) vulnerability, which…
All CVEs affecting Merge-deep Project Merge-deep →
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