CVE-2026-21717
A flaw in V8's string hashing mechanism causes integer-like strings to be hashed to their numeric value, making hash collisions trivially…
- Published
- Updated
- Reserved
- Assigned by
- hackerone
Description
A flaw in V8's string hashing mechanism causes integer-like strings to be hashed to their numeric value, making hash collisions trivially predictable. By crafting a request that causes many such collisions in V8's internal string table, an attacker can significantly degrade performance of the Node.js process. The most common trigger is any endpoint that calls `JSON.parse()` on attacker-controlled input, as JSON parsing automatically internalizes short strings into the affected hash table. This vulnerability affects **20.x, 22.x, 24.x, and 25.x**.
Timeline
ID reserved
By hackerone
- 3 months later
· 3 months later
Published
- 41 days later
· 41 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| hackeroneCNA (assigner) | 3.0 | Medium5.9 | CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H |
| NVDNVD · Analyzed | 3.1 | Medium5.9 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.27% · top 80% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.9.
Weakness
Affected products
- affected 20.20.1 – ≤ 20.20.1
- affected 22.22.1 – ≤ 22.22.1
- affected 24.14.0 – ≤ 24.14.0
- affected 25.8.1 – ≤ 25.8.1
- affected 4.0 – < 4.*
- affected 5.0 – < 5.*
- affected 6.0 – < 6.*
- affected 7.0 – < 7.*
- affected 8.0 – < 8.*
- affected 9.0 – < 9.*
- affected 10.0 – < 10.*
- affected 11.0 – < 11.*
- affected 12.0 – < 12.*
- affected 13.0 – < 13.*
- affected 14.0 – < 14.*
- affected 15.0 – < 15.*
- affected 16.0 – < 16.*
- affected 17.0 – < 17.*
- affected 18.0 – < 18.*
- affected 19.0 – < 19.*
References (1)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-21717)Record last updated .