CVE-2026-49440

7.4 HIGH 0.2% exploit odds Fix listed Other

What it is

Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.8.1, node:crypto.checkPrime(candidate[, options][, callback]) and crypto.checkPrimeSync(candidate[, options]) ran no Miller-Rabin rounds at all when the caller left options.checks at its default of 0. In that mode, the only test applied to the candidate was trial division by the primes up to 17,863. Any composite whose smallest prime factor exceeds that bound — for example the product of two primes just above it, such as 17,881 × 17,891 — was reported as true ("probably prime"). The same divergence affected the lower-level op_node_check_prime / op_node_check_prime_bytes paths that the polyfill calls into. This vulnerability is fixed in 2.8.1.

At a glance

Exploitability: Can be exploited over the network without logging in. High risk of data exposure, data tampering.
Exploit odds: 0.2% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-06-23 18:18 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-10-25 23:10 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.2% in the next 30 days (EPSS).
Severity: 7.4 HIGH (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-06-23 18:18 UTC
Last modified: 2026-10-25 23:10 UTC
Exploit probability: 0.2% · EPSS, next 30 days
Weakness: CWE-325
Record status: Analyzed

Affected

Deno < 2.8.1

Attack profile CVSS 3.1 · 7.4

Attack vector: Network
Complexity: High
Privileges needed: None
User interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: None

Raw vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Is it in your code?

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Fix and advisories

References

NVD record · CVE.org record