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Vulnerabilities

Vulnerability · 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 predictable.

Published Mar 30, 2026 · catalog updated Aug 19, 2026 · A flaw in V8's

Check if you run it

No confirmed exploitation is on record for CVE-2026-21717. EPSS is 0.27%. Act only if a listed version of A flaw in V8's is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (A flaw in V8's).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium5.9
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.27%
Remediation
Advisory link
Affected products
cpe nodejs/node.js

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 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**.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe nodejs/node.jsversion unspecified

How to fix CVE-2026-21717

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-21717. EPSS is 0.27%. Act only if a listed version of A flaw in V8's is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-328. EPSS 0.27%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Mar 30, 2026 · NIST NVD

    Detected

    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 on attacker-controlled input, as JSON

  2. Aug 19, 2026 · NIST NVD

    Updated

    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 on attacker-controlled input, as JSON

Sources

  • CVE.orgVulnerability recordCVE-2026-21717

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-21717

    30-day exploitation probability 0.3%

    first.org
  • NIST NVDVulnerability recordCVE-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 predictable. By crafting a request that causes many such collisions in V8's internal string table, an attacker can significantly degrade perfo

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.