How severe is CVE-2026-26021?

CVE-2026-26021 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-2026-26021 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (37th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-26021?

CVE-2026-26021 affects Set-in Project Set-in. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-26021?

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.

Does CVE-2026-26021 have an EU (EUVD) identifier?

Yes. CVE-2026-26021 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-6208.

When was CVE-2026-26021 published?

CVE-2026-26021 was published on 2026-02-11 and last updated on 2026-06-17.

CVE-2026-26021

CVE-2026-26021 is a critical-severity vulnerability in Set-in Project Set-in 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 v4: 9.4
EPSS exploit prediction: 0% (37th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-6208
Weakness: CWE-1321
Affected product: Set-in Project Set-in
Published: 2026-02-11
Last modified: 2026-06-17

Description

set-in provides the set value of nested associative structure given array of keys. A prototype pollution vulnerability exists in the the npm package set-in (>=2.0.1, < 2.0.5). Despite a previous fix that attempted to mitigate prototype pollution by checking whether user input contained a forbidden key, it is still possible to pollute Object.prototype via a crafted input using Array.prototype. This has been fixed in version 2.0.5.

Frequently asked questions

What is CVE-2026-26021?: set-in provides the set value of nested associative structure given array of keys. A prototype pollution vulnerability exists in the the npm package set-in (>=2.0.1, < 2.0.5). Despite a previous fix that attempted to mitigate prototype pollution by checking whether user input contained a forbidden key, it is still possible to pollute Object.prototype via a crafted input using Array.prototype. This has been fixed in version 2.0.5.
How severe is CVE-2026-26021?: CVE-2026-26021 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-2026-26021 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (37th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-26021?: CVE-2026-26021 affects Set-in Project Set-in. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-26021?: 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.
Does CVE-2026-26021 have an EU (EUVD) identifier?: Yes. CVE-2026-26021 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-6208.
When was CVE-2026-26021 published?: CVE-2026-26021 was published on 2026-02-11 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:set-in_project:set-in:*:*:*:*:*:*:*:*

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