Machine-written summary
Summary written by Claude Haiku from the source advisory. Not reviewed by a person.
The devalue npm package, versions before 5.9.3, is affected. An application that passes attacker-influenced sparse arrays to the uneval function can have its event loop blocked, because the function does synchronous work proportional to the array's declared length. The source notes that attacker-controlled creation of sparse arrays is difficult, so exploitation is considered very difficult. Upgrade devalue to version 5.9.3 or later.
Not analysed yet
We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.
Severity and exploitation
| Score | Rating | CVSS | Vector | Source |
|---|---|---|---|---|
| 8.7 | High | 4.0 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N | CNA (VulnCheck) |
- CISA KEV Not listed.
- EPSS 0.0034, the 28th percentile, on 13 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.
Timeline
- 31 Oct 2026, 13:34 UTC First seen by agentprime
- 31 Oct 2026, 13:34 UTC Confirmed by OSV
- 8 Nov 2026, 01:45 UTC Confirmed by the CVE List
- 8 Nov 2026, 02:21 UTC Confirmed by NVD