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High 7.4Published Jun 23, 2026

CVE-2026-49440Deno is a JavaScript, TypeScript, and WebAssembly runtime.

Updated under an hour ago ()

Does this affect you?

It affects deno. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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.

CVSS
7.4 HIGH (v3.1, NVD)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Weakness (CWE)
CWE-325
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
Not given
NVD analysis
Analyzed
Record last updated
Jun 26, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
deno deno
deno:deno
before 2.8.1
NVD

References

  • issue-tracking
  • third-party-advisory

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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