CVE-2026-49859

MEDIUMPre-NVD 5.25.2—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.2 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
5.2EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.2Exploit: None knownExposed: 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, when fetch() was called, Deno checked the destination hostname against --deny-net rules but did not re-check the IP addresses that hostname resolved to. An attacker-controlled script could use a specially crafted domain name that passes the hostname check yet resolves to a denied IP, bypassing the network restriction entirely. This vulnerability is fixed in 2.8.1.

CVSS v3
5.2
EG Score
5.2(medium)
EG Risk
28(Track)
EG Risk 28/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity52% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
4%
KEV
Not listed

Published

June 16, 2026

Last Modified

June 29, 2026

Advisory Details (1)

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

`fetch()` API sandbox bypass via missing DNS resolution check · Advisory · denoland/deno · GitHub

https://github.com/denoland/deno/security/advisories/GHSA-cpgj-f7g3-2pp2

Vendor Advisories for CVE-2026-49859(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(2)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 39× 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. 2026-08-25 13:49 UTCEPSS rescore
  2. 2026-08-24 23:24 UTCEG score recompute
  3. 2026-08-23 09:25 UTCEG score recompute
  4. 2026-08-23 00:19 UTCEPSS rescore
  5. 2026-08-21 23:49 UTCEPSS rescore
  6. 2026-08-21 12:14 UTCEG score recompute
  7. 2026-08-20 22:55 UTCEPSS rescore
  8. 2026-08-20 12:41 UTCEG score recompute
  9. 2026-08-19 17:04 UTCEPSS rescore
  10. 2026-08-19 13:07 UTCEG score recompute
  11. 2026-08-18 13:48 UTCEPSS rescore
  12. 2026-08-17 13:47 UTCEPSS rescore
  13. 2026-08-16 21:58 UTCEG score recompute
  14. 2026-08-16 02:14 UTCEPSS rescore
  15. 2026-08-15 19:23 UTCEG score recompute
  16. 2026-08-15 01:30 UTCEPSS rescore
  17. 2026-08-14 19:50 UTCEG score recompute
  18. 2026-08-13 22:00 UTCEPSS rescore
  19. 2026-08-11 19:10 UTCEG score recompute
  20. 2026-08-11 00:00 UTCEPSS rescore
  21. 2026-08-08 17:59 UTCEG score recompute
  22. 2026-08-08 16:37 UTCEPSS rescore
  23. 2026-08-07 18:25 UTCEG score recompute
  24. 2026-08-06 18:52 UTCEG score recompute
  25. 2026-08-06 13:47 UTCEPSS rescore
Show 46 more
  1. 2026-08-05 19:19 UTCEG score recompute
  2. 2026-08-05 19:17 UTCEPSS rescore
  3. 2026-08-04 15:36 UTCEG score recompute
  4. 2026-08-04 15:10 UTCEPSS rescore
  5. 2026-08-03 10:36 UTCEPSS rescore
  6. 2026-08-01 08:19 UTCEG score recompute
  7. 2026-08-01 04:16 UTCEPSS rescore
  8. 2026-07-31 04:24 UTCEG score recompute
  9. 2026-07-30 16:28 UTCEPSS rescore
  10. 2026-07-30 04:14 UTCEG score recompute
  11. 2026-07-30 01:30 UTCEPSS rescore
  12. 2026-07-29 03:03 UTCEG score recompute
  13. 2026-07-28 15:37 UTCEPSS rescore
  14. 2026-07-28 01:38 UTCEG score recompute
  15. 2026-07-26 19:50 UTCEG score recompute
  16. 2026-07-25 14:18 UTCEPSS rescore
  17. 2026-07-24 14:18 UTCEPSS rescore
  18. 2026-07-23 14:18 UTCEPSS rescore
  19. 2026-07-23 03:18 UTCEG score recompute
  20. 2026-07-22 14:08 UTCEPSS rescore
  21. 2026-07-20 17:08 UTCEPSS rescore
  22. 2026-07-19 02:29 UTCEPSS rescore
  23. 2026-07-18 10:04 UTCEPSS rescore
  24. 2026-07-16 17:03 UTCEPSS rescore
  25. 2026-07-15 16:57 UTCEPSS rescore
  26. 2026-07-15 16:57 UTCEPSS rescore
  27. 2026-07-15 02:00 UTCEPSS rescore
  28. 2026-07-13 22:30 UTCEPSS rescore
  29. 2026-07-13 06:13 UTCEPSS rescore
  30. 2026-07-12 05:46 UTCEPSS rescore
  31. 2026-07-09 19:10 UTCEPSS rescore
  32. 2026-07-08 15:16 UTCEPSS rescore
  33. 2026-07-07 13:46 UTCEPSS rescore
  34. 2026-07-06 02:23 UTCEPSS rescore
  35. 2026-07-04 06:31 UTCEPSS rescore
  36. 2026-07-01 15:07 UTCEPSS rescore
  37. 2026-06-30 23:22 UTCEPSS rescore
  38. 2026-06-29 14:06 UTCEPSS rescore
  39. 2026-06-29 14:06 UTCEPSS rescore
  40. 2026-06-28 14:07 UTCEPSS rescore
  41. 2026-06-28 04:56 UTCEPSS rescore
  42. 2026-06-28 04:56 UTCEPSS rescore
  43. 2026-06-27 03:08 UTCEPSS rescore
  44. 2026-06-25 13:49 UTCEPSS rescore
  45. 2026-06-24 14:05 UTCEPSS rescore
  46. 2026-06-16 19:06 UTCEG score recompute

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-49859?
CVE-2026-49859 is a medium vulnerability published on June 16, 2026. Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.8.1, when fetch() was called, Deno checked the destination hostname against --deny-net rules but did not re-check the IP addresses that hostname resolved to. An attacker-controlled script could use a specially crafted domain name…
When was CVE-2026-49859 disclosed?
CVE-2026-49859 was first published in the National Vulnerability Database on June 16, 2026, with the most recent update on June 29, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-49859 actively exploited?
CVE-2026-49859 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 96.3% of all scored CVEs.
What is the CVSS score of CVE-2026-49859?
CVE-2026-49859 has a CVSS v3 base score of 5.2 (NVD).
How do I remediate CVE-2026-49859?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-49859, 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.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-49859

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