Prototype pollution in set-in
Priority HIGH 76CWE-1321Published · Updated
Key facts
- Attack vector
- Local
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub.
Summary
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.
Why it matters now
Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00557 46th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed set-in (ahdinosaur): 2.0.5set-in (npm): 2.0.5
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| ahdinosaur | set-in | 2.0.1 to before 2.0.5 | 2.0.5 | Patch available | CNA |
| — | set-in (npm) | 2.0.1 to before 2.0.5 | 2.0.5 | Patch available | GHSA-2c4m-g7rx-63q7 |
- set-in Vendorahdinosaur Affected 2.0.1 to before 2.0.5 Fixed in 2.0.5 Patch available CNA
- set-in (npm) Vendor— Affected 2.0.1 to before 2.0.5 Fixed in 2.0.5 Patch available GHSA-2c4m-g7rx-63q7
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:set-in_project:set-in:*:*:*:*:*:*:*:* | 2.0.1 to before 2.0.5 | Vulnerable | Set-in Project |
- cpe:2.3:a:set-in_project:set-in:*:*:*:*:*:*:*:* Versions 2.0.1 to before 2.0.5 Vulnerable ·Set-in Project
Remediation
- Fix · CNA set-in (ahdinosaur) Fixed in 2.0.5
- Fix · GHSA-2c4m-g7rx-63q7 set-in (npm) Fixed in 2.0.5 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2026-26021
- 2026-10-03 Alias added: GHSA-2c4m-g7rx-63q7
References
Other 5
- https://github.com/ahdinosaur/set-in/pull/6
- https://github.com/ahdinosaur/set-in/commit/34842cc02de3fd65d6f8bd0b268347e7b390125b
- https://github.com/ahdinosaur/set-in/commit/6bad255961d379e4b1f5fbc52ef9dc8420816f24
- https://github.com/ahdinosaur/set-in/commit/d87c1a09fa2edb55cd76440a67d83d1cb828df11
- https://github.com/ahdinosaur/set-in
More Set-in Project Set-in vulnerabilities
- TI-2020-17167 Prototype pollution in set-in CVSS 3.1CRITICAL 9.8
- TI-2022-09041 Prototype pollution in set-in CVSS 3.1CRITICAL 9.8
Sources
- CVE-2026-26021 · CVE Program
- CVE-2026-26021 · NVD
- FIRST EPSS
- GHSA-2c4m-g7rx-63q7 · GitHub Advisory Database · CC BY 4.0
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