CVE-2026-84373

MEDIUMPre-NVD 5.95.9
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

This medium-severity CVE scores 5.9 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.5% (44th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source
Trending — 3 sources updated this week

Also known asEUVD-2026-69705 (ENISA EUVD) · GHSA-82fw-gwwq-j7x9 (GitHub Security Advisories)Source: ENISA EUVD

5.9EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.5%CVSS: 5.9Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Vitest is a testing framework powered by Vite. From 2.1.0 until 4.1.11 and 5.0.0-rc.2, the public mockerPlugin and standalone interceptorPlugin exports in packages/mocker/src/node/interceptorPlugin.ts register the vitest:interceptor:register handler on Vite's unauthenticated HMR WebSocket without validating redirect targets against the file-serving allowlist. The implementation processes event.redirect without enforcing server.fs.allow and server.fs.deny through isFileLoadingAllowed. A remote client that can reach an exposed development server can submit an opaque URL scheme preserving .. segments, causing join(server.config.root, redirectUrl.pathname) to resolve outside the project root. The plugin's load hook then returns readFile(mock.redirect, 'utf-8') as module source, disclosing local files readable by the dev-server process. Vitest browser mode uses a token-authenticated RPC and is not remotely unauthenticated by default, although the same boundary check was missing on that path. This issue is fixed in versions 4.1.11 and 5.0.0-rc.2.

CVSS v3
5.9
EG Score
5.9MEDIUMmedium confidence
EG Risk
27
EG Risk 27/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity59% × 45%
Impact severity (EG Severity): CVSS 5.9 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.5% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.5%
EPSS %ILE
44th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (5.9): severity, escalated by confirmed exploitation. This CVE's 5.9 is its impact severity (EG Severity), not escalated.

EG Severity
5.9 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.a secondary CVSS source · CVSS v3.0 or v3.1
EG Likelihood
0.5% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-24). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

September 1, 2026

Last Modified

September 9, 2026

Advisory Details (8)

Auto-updated Sep 1, 2026
Patch available. Sources: github, github_pr, github_commit, github_release.
GitHub release Patch Available

v5.0.0-rc.2

Patch available: vitest-dev/vitest v5.0.0-rc.2 (pre-release)

https://github.com/vitest-dev/vitest/releases/tag/v5.0.0-rc.2
GitHub release Patch Available

v4.1.11

Patch available: vitest-dev/vitest v4.1.11

https://github.com/vitest-dev/vitest/releases/tag/v4.1.11
GitHub commit Patch Available

commit fe5a11d3ceac (vitest-dev/vitest)

Patch available: vitest-dev/vitest v4.1.11 (contains commit fe5a11d3ceac)

https://github.com/vitest-dev/vitest/commit/fe5a11d3ceac5ec10d6d7d21a46d4caca132c48f
GitHub commit Patch Available

commit 8ff9b9a9efca (vitest-dev/vitest)

Patch available: vitest-dev/vitest v5.0.0-rc.2 (contains commit 8ff9b9a9efca)

https://github.com/vitest-dev/vitest/commit/8ff9b9a9efca7c6cfd5243569440de8d7a33aec4
GitHub commit

commit 51edf2b07290 (vitest-dev/vitest)

Fix landed in vitest-dev/vitest commit 51edf2b07290 — awaiting tagged release

https://github.com/vitest-dev/vitest/commit/51edf2b072902aec6d30c90ebaafd8f121c6f9d8
GitHub pull request Patch Available

fix(mocker): restrict redirect mocks to the fs allowlist [backport to v4]

Patch available: vitest-dev/vitest v4.1.11 (PR #10974 merged 2026-08-17)

https://github.com/vitest-dev/vitest/pull/10974
GitHub pull request Patch Available

fix(mocker): restrict redirect mocks to the fs allowlist

Patch available: vitest-dev/vitest v5.0.0-rc.2 (PR #10972 merged 2026-08-17)

https://github.com/vitest-dev/vitest/pull/10972
GitHub advisoryMentions a patch (unverified)

Path Traversal / Arbitrary File Read via @vitest/mocker Redirect Mock · Advisory · vitest-dev/vitest · GitHub

https://github.com/vitest-dev/vitest/security/advisories/GHSA-82fw-gwwq-j7x9

Vendor Advisories for CVE-2026-84373(1)

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

Affected Packages

(2 across 1 ecosystem)
npm(2)
PackageVulnerable rangeFix by version rangeDependents
vitest—
  • 2.1.0 up to 4.1.11: fixed in 4.1.11
  • 5.0.0-beta.1 up to 5.0.0-rc.2: fixed in 5.0.0-rc.2
—
@vitest/mocker—
  • 2.1.0 up to 4.1.11: fixed in 4.1.11
  • 5.0.0-beta.1 up to 5.0.0-rc.2: fixed in 5.0.0-rc.2
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 9× in last 7d / 46× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 2 repeat rows among the latest 96 are merged into the row they repeat.

  1. 2026-10-30 16:35 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  2. 2026-10-30 00:55 UTCOSV refresh
  3. 2026-10-29 16:34 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  4. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  5. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  6. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  7. 2026-10-25 16:34 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  8. 2026-10-25 13:56 UTCEG score recompute
  9. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  10. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  11. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  12. 2026-10-22 13:14 UTCEG score recompute
  13. 2026-10-21 16:34 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  14. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  15. 2026-10-19 16:33 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  16. 2026-10-18 16:33 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  17. 2026-10-18 03:06 UTCEG score recompute
  18. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  19. 2026-10-16 16:44 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  20. 2026-10-15 16:33 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  21. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  22. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  23. 2026-10-12 16:35 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  24. 2026-10-12 14:53 UTCEG score recompute
  25. 2026-10-11 19:18 UTCEG score recompute
Show 69 more
  1. 2026-10-11 16:35 UTCEG score recompute
  2. 2026-10-11 13:52 UTCEG score recompute
  3. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  4. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  5. 2026-10-10 03:54 UTCEG score recompute
  6. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  7. 2026-10-09 01:50 UTCEG score recompute
  8. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  9. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  10. 2026-10-07 09:23 UTCEG score recompute
  11. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  12. 2026-10-06 07:20 UTCEG score recompute
  13. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  14. 2026-10-05 04:33 UTCEG score recompute
  15. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  16. 2026-10-04 02:29 UTCEG score recompute
  17. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  18. 2026-10-03 00:25 UTCEG score recompute
  19. 2026-10-02 17:57 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  20. 2026-10-01 21:31 UTCEG score recompute
  21. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  22. 2026-09-30 19:28 UTCEG score recompute
  23. 2026-09-30 15:04 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  24. 2026-09-29 11:52 UTCEG score recompute
  25. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  26. 2026-09-28 09:16 UTCEG score recompute
  27. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  28. 2026-09-27 07:13 UTCEG score recompute
  29. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  30. 2026-09-26 05:09 UTCEG score recompute
  31. 2026-09-25 02:20 UTCEG score recompute
  32. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  33. 2026-09-24 00:16 UTCEG score recompute
  34. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  35. 2026-09-22 22:13 UTCEG score recompute
  36. 2026-09-22 16:01 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  37. 2026-09-21 21:09 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  38. 2026-09-21 20:10 UTCEG score recompute
  39. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  40. 2026-09-19 16:01 UTCEG score recompute
  41. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  42. 2026-09-18 13:42 UTCEG score recompute
  43. 2026-09-17 19:32 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  44. 2026-09-17 11:38 UTCEG score recompute
  45. 2026-09-16 14:09 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  46. 2026-09-16 09:32 UTCEG score recompute
  47. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  48. 2026-09-15 07:28 UTCEG score recompute
  49. 2026-09-15 03:12 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  50. 2026-09-14 05:25 UTCEG score recompute
  51. 2026-09-13 03:22 UTCEG score recompute
  52. 2026-09-12 01:18 UTCEG score recompute
  53. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  54. 2026-09-10 23:14 UTCEG score recompute
  55. 2026-09-09 02:59 UTCEG score recompute
  56. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  57. 2026-09-08 00:55 UTCEG score recompute
  58. 2026-09-06 22:51 UTCEG score recompute
  59. 2026-09-06 13:48 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  60. 2026-09-05 20:46 UTCEG score recompute
  61. 2026-09-05 15:31 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  62. 2026-09-04 18:43 UTCEG score recompute
  63. 2026-09-04 05:07 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  64. 2026-09-02 14:29 UTCEG score recompute
  65. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  66. 2026-09-02 13:34 UTCEG score recompute
  67. 2026-09-01 22:19 UTCEG score recompute
  68. 2026-09-01 21:33 UTCEG score recomputeFirst assessed: 5.9 MEDIUM
  69. 2026-09-01 21:32 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-84373?
CVE-2026-84373 is a medium-severity vulnerability; its CVE record was published on September 1, 2026. Vitest is a testing framework powered by Vite. From 2.1.0 until 4.1.11 and 5.0.0-rc.2, the public mockerPlugin and standalone interceptorPlugin exports in packages/mocker/src/node/interceptorPlugin.ts register the vitest:interceptor:register handler on Vite's unauthenticated HMR WebSocket without…
When was the CVE record for CVE-2026-84373 published?
The CVE record for CVE-2026-84373 was published on September 1, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of September 9, 2026; the record at its source may have been updated since.
Is CVE-2026-84373 actively exploited?
CVE-2026-84373 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.5% probability of exploitation in the next 30 days (44th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-84373?
CVE-2026-84373 has a CVSS base score of 5.9 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-84373?
A fix for CVE-2026-84373 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-84373 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-84373

Explore →

Is Your Infrastructure Affected by CVE-2026-84373?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.