Node: A flaw in V8's string hashing mechanism causes integer-like strings to be hashed to their numeric value, making hash collisions trivially predictable. (CVE-2026-21717)
A vulnerability in the V8 JavaScript engine used by Node.js causes integer-like strings to hash to their numeric value, making hash collisions predictable. This can be exploited by an attacker to degrade Node.js process performance by triggering many collisions, commonly via JSON.parse() on attacker-controlled input. The flaw affects multiple Node.js versions including 20.x, 22.x, 24.x, and 25.x. A patch is available to address this issue.
AI Analysis
Technical Summary
The vulnerability (CVE-2026-21717) resides in V8's string hashing mechanism where integer-like strings are hashed to their numeric value, resulting in trivially predictable hash collisions. Attackers can exploit this by crafting requests that cause numerous collisions in V8's internal string table, significantly degrading performance of the Node.js process. The typical attack vector involves endpoints that call JSON.parse() on attacker-controlled input, as JSON parsing internalizes short strings into the affected hash table. Affected Node.js versions include 20.x, 22.x, 24.x, and 25.x, with specific vulnerable version ranges documented. A patch is available to mitigate this issue.
Potential Impact
Exploitation of this vulnerability allows an attacker to cause significant performance degradation of the Node.js process by triggering predictable hash collisions in V8's string table. This can lead to denial of service conditions due to resource exhaustion or slowdowns. There are no known exploits in the wild at this time.
Mitigation Recommendations
A patch is available for this vulnerability. Users should update Node.js to patched versions beyond the affected ranges to remediate the issue. Specific vulnerable versions include =3.0, =2.0, <20.20.2, >=21.0.0 <22.22.2, >=23.0.0 <24.14.1, and >=25.0.0 <25.8.2. Applying these updates will mitigate the risk of performance degradation caused by this flaw.
Node: A flaw in V8's string hashing mechanism causes integer-like strings to be hashed to their numeric value, making hash collisions trivially predictable. (CVE-2026-21717)
Description
A vulnerability in the V8 JavaScript engine used by Node.js causes integer-like strings to hash to their numeric value, making hash collisions predictable. This can be exploited by an attacker to degrade Node.js process performance by triggering many collisions, commonly via JSON.parse() on attacker-controlled input. The flaw affects multiple Node.js versions including 20.x, 22.x, 24.x, and 25.x. A patch is available to address this issue.
Affected software
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability (CVE-2026-21717) resides in V8's string hashing mechanism where integer-like strings are hashed to their numeric value, resulting in trivially predictable hash collisions. Attackers can exploit this by crafting requests that cause numerous collisions in V8's internal string table, significantly degrading performance of the Node.js process. The typical attack vector involves endpoints that call JSON.parse() on attacker-controlled input, as JSON parsing internalizes short strings into the affected hash table. Affected Node.js versions include 20.x, 22.x, 24.x, and 25.x, with specific vulnerable version ranges documented. A patch is available to mitigate this issue.
Potential Impact
Exploitation of this vulnerability allows an attacker to cause significant performance degradation of the Node.js process by triggering predictable hash collisions in V8's string table. This can lead to denial of service conditions due to resource exhaustion or slowdowns. There are no known exploits in the wild at this time.
Mitigation Recommendations
A patch is available for this vulnerability. Users should update Node.js to patched versions beyond the affected ranges to remediate the issue. Specific vulnerable versions include =3.0, =2.0, <20.20.2, >=21.0.0 <22.22.2, >=23.0.0 <24.14.1, and >=25.0.0 <25.8.2. Applying these updates will mitigate the risk of performance degradation caused by this flaw.
Technical Details
- Gcve Source
- db.gcve.eu
- Csaf Category
- csaf_vex
- Csaf Version
- 2.0
- Publisher
- Microsoft Security Response Center
- Advisory Id
- msrc_CVE-2026-21717
- Cve Count
- 1
- State
- PUBLISHED
Threat ID: 6a1ca153e29bf47b505e07c3
Added to database: 05/31/2026, 21:00:03 UTC
Last enriched: 09/08/2026, 15:18:04 UTC
Last updated: 09/13/2026, 22:01:32 UTC
Views: 165
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