CVE-2026-49440

HIGHPre-NVD 7.47.4—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.4 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.1%, top 96% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
7.4
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.4Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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 v3
7.4
EG Score
7.4(medium)
EPSS
4.5%
KEV
Not listed

Published

June 16, 2026

Last Modified

June 26, 2026

Advisory Details (2)

Auto-updated Jun 23, 2026
Patch available. Sources: github_pr, github.
github Patch Available

Miller-Rabin Primality Test Allows Zero Rounds · Advisory · denoland/deno · GitHub

https://github.com/denoland/deno/security/advisories/GHSA-9xg4-qhm4-g43w
github_pr

fix(ext/node): enforce minimum Miller-Rabin rounds in checkPrime

Fix merged in denoland/deno PR #34391 on 2026-05-26 — awaiting tagged release

https://github.com/denoland/deno/pull/34391

Vendor Advisories for CVE-2026-49440(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
crates.io(1)
PackageVulnerable rangeFixed inDependents
deno—2.8.1—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 16× in last 7d / 51× 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.

  1. 2026-07-06 23:09 UTCEG score recompute
  2. 2026-07-06 02:23 UTCEPSS rescore
  3. 2026-07-05 22:47 UTCEG score recompute
  4. 2026-07-05 10:17 UTCEG score recompute
  5. 2026-07-05 02:30 UTCEPSS rescore
  6. 2026-07-04 21:35 UTCEG score recompute
  7. 2026-07-04 09:08 UTCEG score recompute
  8. 2026-07-04 06:31 UTCEPSS rescore
  9. 2026-07-03 13:47 UTCEG score recompute
  10. 2026-07-02 22:31 UTCEG score recompute
  11. 2026-07-02 10:05 UTCEG score recompute
  12. 2026-07-01 21:38 UTCEG score recompute
  13. 2026-07-01 15:07 UTCEPSS rescore
  14. 2026-07-01 09:11 UTCEG score recompute
  15. 2026-06-30 23:22 UTCEPSS rescore
  16. 2026-06-30 20:44 UTCEG score recompute
  17. 2026-06-30 08:12 UTCEG score recompute
  18. 2026-06-29 19:46 UTCEG score recompute
  19. 2026-06-29 14:06 UTCEPSS rescore
  20. 2026-06-29 14:06 UTCEPSS rescore
  21. 2026-06-29 07:20 UTCEG score recompute
  22. 2026-06-28 18:53 UTCEG score recompute
  23. 2026-06-28 14:07 UTCEPSS rescore
  24. 2026-06-28 06:26 UTCEG score recompute
  25. 2026-06-28 04:56 UTCEPSS rescore
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  1. 2026-06-28 04:56 UTCEPSS rescore
  2. 2026-06-27 17:59 UTCEG score recompute
  3. 2026-06-27 05:32 UTCEG score recompute
  4. 2026-06-27 03:08 UTCEPSS rescore
  5. 2026-06-26 17:05 UTCEG score recompute
  6. 2026-06-26 04:39 UTCEG score recompute
  7. 2026-06-25 16:12 UTCEG score recompute
  8. 2026-06-25 13:49 UTCEPSS rescore
  9. 2026-06-25 03:45 UTCEG score recompute
  10. 2026-06-24 15:09 UTCEG score recompute
  11. 2026-06-24 14:05 UTCEPSS rescore
  12. 2026-06-24 02:43 UTCEG score recompute
  13. 2026-06-23 14:16 UTCEG score recompute
  14. 2026-06-23 01:16 UTCEG score recompute
  15. 2026-06-22 12:48 UTCEG score recompute
  16. 2026-06-22 00:19 UTCEG score recompute
  17. 2026-06-21 11:53 UTCEG score recompute
  18. 2026-06-20 23:26 UTCEG score recompute
  19. 2026-06-20 10:58 UTCEG score recompute
  20. 2026-06-19 22:29 UTCEG score recompute
  21. 2026-06-19 10:00 UTCEG score recompute
  22. 2026-06-18 21:33 UTCEG score recompute
  23. 2026-06-18 09:06 UTCEG score recompute
  24. 2026-06-17 20:36 UTCEG score recompute
  25. 2026-06-17 08:10 UTCEG score recompute
  26. 2026-06-16 19:44 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-49440?
CVE-2026-49440 is a high vulnerability published on June 16, 2026. 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…
When was CVE-2026-49440 disclosed?
CVE-2026-49440 was first published in the National Vulnerability Database on June 16, 2026, with the most recent update on June 26, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-49440 actively exploited?
CVE-2026-49440 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 4.5% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-49440?
CVE-2026-49440 has a CVSS v3 base score of 7.4 (NVD).
How do I remediate CVE-2026-49440?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-49440, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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