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.
CVE-2026-21717
Score 5.9 from GitHub Security Advisory published 2026-03-30. NVD baseline CVSS 5.9; sources differ by 0.0.
- Lower severity and no public exploit yet
A fix is available — apply it.
- CVSS v3
- 5.9
- EG Score
- 5.9(medium)
- EPSS
- 20.2%
- KEV
- Not listed
Published
March 30, 2026
Last Modified
May 10, 2026
Advisory Details (1)
Auto-updated May 10, 2026Node.js — Tuesday, March 24, 2026 Security Releases
https://nodejs.org/en/blog/vulnerability/march-2026-security-releasesVendor Advisories for CVE-2026-21717(8)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
- CVE-2026-21717Microsoft Security Response Center (MSRC)Medium
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**.
- RHSA-2026:7670Red Hat Product SecurityHigh
Red Hat Security Advisory: nodejs:24 security update
- RHSA-2026:7675Red Hat Product SecurityHigh
Red Hat Security Advisory: nodejs24 security update
- RHSA-2026:7387Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update
- RHSA-2026:7386Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update
- RHSA-2026:7350Red Hat Product SecurityHigh
Red Hat Security Advisory: nodejs:24 security update
- RHSA-2026:6431Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update
- RHSA-2026:6402Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update
Patch Availability(7)
| Vendor / Ecosystem | Fixed in / Patch | Released | Source |
|---|---|---|---|
| redhat | nodejs24-1:24.14.1-2.el10_1 | 2026-04-13 | redhat |
| redhat | nodejs:24-8100020260408131901.6d880403 | 2026-04-13 | redhat |
| redhat | nodejs22-main-22.22.0-1.3.hum1 | 2026-04-10 | redhat |
| redhat | nodejs20-main-20.20.0-7.1.hum1 | 2026-04-10 | redhat |
| redhat | nodejs:24-9070020260402152654.rhel9 | 2026-04-09 | redhat |
| redhat | nodejs25-main-25.9.0-1.hum1 | 2026-04-02 | redhat |
| redhat | nodejs24-main-24.14.1-4.hum1 | 2026-04-01 | redhat |
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 11× in last 7d / 40× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
Showing the most recent 100 of 106 total refreshes for this CVE.
- 2026-07-12 05:46 UTCEPSS rescore
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- 2026-07-11 08:27 UTCEPSS rescore
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- 2026-06-22 14:25 UTCEPSS rescore
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- 2026-06-11 22:46 UTCVendor advisory
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- 2026-06-11 14:00 UTCEPSS rescore
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- 2026-06-10 15:36 UTCEG score recompute
- 2026-06-10 15:36 UTCVendor advisory
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- 2026-06-10 13:22 UTCEPSS rescore
- 2026-06-09 15:13 UTCEG score recompute
- 2026-06-09 15:13 UTCVendor advisory
- 2026-06-09 15:13 UTCGHSA enrichment
- 2026-06-08 14:17 UTCEPSS rescore
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- 2026-06-08 13:05 UTCEG score recompute
- 2026-06-08 13:05 UTCVendor advisory
- 2026-06-08 13:05 UTCGHSA enrichment
- 2026-06-07 15:25 UTCEPSS rescore
- 2026-06-07 15:24 UTCEPSS rescore
- 2026-06-07 11:42 UTCEG score recompute
- 2026-06-07 11:42 UTCVendor advisory
- 2026-06-07 11:42 UTCGHSA enrichment
- 2026-06-06 13:47 UTCEPSS rescore
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- 2026-05-20 19:54 UTCEG score recompute
Frequently asked(5)
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