CVE-2026-42211

HIGHPre-NVD 8.18.1
EchelonGraph scoreMEDIUM confidence

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

This high-severity CVE scores 8.1 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.6% (49th 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
8.1EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.6%CVSS: 8.1Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

React Router is a router for React. In versions 7.0.0 through 7.14.1, when using Framework Mode, a combination of steps could potentially allow unauthorized remote code execution (RCE) through external requests. This attack requires the application code to have an existing prototype pollution vulnerability, which can then be leveraged in a 2-step attack where the second step triggers unauthorized RCE on the remote server. This does not impact applications using Declarative Mode (`) or Data Mode (createBrowserRouter/`). This is patched in version 7.14.2.

CVSS v3
8.1
EG Score
8.1HIGHmedium confidence
EG Risk
37
EG Risk 37/100

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)
Severity81% × 45%
Impact severity (EG Severity): CVSS 8.1 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.6% × 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 low or medium mission impact; Track* at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (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
0.6%
EPSS %ILE
49th
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 (8.1): severity, escalated by confirmed exploitation. This CVE's 8.1 is its impact severity (EG Severity), not escalated.

EG Severity
8.1 HIGHCVSS-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
0.6% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-17). 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 low or medium mission impact; Track* at high (mission-essential systems).CISA BOD 26-04: 14 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 low or medium mission impact; Track* at high (mission-essential systems).

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

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (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)14 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 total (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

June 2, 2026

Last Modified

July 21, 2026

Advisory Details (1)

Auto-updated Jun 3, 2026
Patch available. Sources: github.
GitHub advisoryMentions a patch (unverified)

Potential RCE via 2-step attack chained onto existing prototype pollution vulnerability · Advisory · remix-run/react-router · GitHub

https://github.com/remix-run/react-router/security/advisories/GHSA-49rj-9fvp-4h2h

Vendor Advisories for CVE-2026-42211(8)

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

Patch Availability(5)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
redhatreact-router2026-09-16redhat
redhatrhbk/keycloak-rhel9-operator:26.6-202026-09-16redhat
redhatrhoai/odh-mod-arch-model-registry-rhel9:17872506172026-08-27redhat
redhatrhtas/rhtas-console-ui-rhel9:17841058942026-07-20redhat
redhatopentelemetry-collector-contrib-main-0.155.0-0.1.hum12026-06-25redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(1 across 1 ecosystem)
npm(1)
PackageVulnerable rangeFix by version rangeDependents
react-router—
  • 7.0.0 up to 7.14.2: fixed in 7.14.2
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 9× in last 7d / 31× 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.

Showing the most recent 100 of 211 refreshes on record for this CVE.

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. None are among the latest 100 rows. The 111 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.6% · 49th percentile
  2. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  3. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  4. 2026-10-18 03:41 UTCEG score recompute
  5. 2026-10-17 16:34 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  6. 2026-10-17 14:29 UTCEG score recompute
  7. 2026-10-17 14:29 UTCVendor advisory
  8. 2026-10-16 16:42 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  9. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  10. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  11. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  12. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  13. 2026-10-12 16:07 UTCEG score recompute
  14. 2026-10-11 19:49 UTCEG score recompute
  15. 2026-10-11 17:03 UTCEG score recompute
  16. 2026-10-11 14:29 UTCEG score recompute
  17. 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  18. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  19. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  20. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  21. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  22. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  23. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  24. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  25. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.6% · 47th percentile
Show 75 more
  1. 2026-10-03 12:39 UTCOSV refresh
  2. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  3. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  4. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  5. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  6. 2026-09-23 17:53 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  7. 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  8. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  9. 2026-09-17 19:31 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  10. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  11. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  12. 2026-09-14 05:44 UTCEG score recompute
  13. 2026-09-14 05:44 UTCVendor advisory
  14. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  15. 2026-09-13 00:06 UTCOSV refresh
  16. 2026-09-12 15:01 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  17. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  18. 2026-09-11 09:37 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  19. 2026-09-10 09:34 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  20. 2026-09-08 22:00 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  21. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  22. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  23. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  24. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  25. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  26. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  27. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  28. 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  29. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  30. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  31. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  32. 2026-08-25 03:44 UTCEG score recompute
  33. 2026-08-25 03:44 UTCVendor advisory
  34. 2026-08-23 13:40 UTCEG score recompute
  35. 2026-08-23 13:40 UTCVendor advisory
  36. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  37. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  38. 2026-08-21 14:44 UTCVendor advisory
  39. 2026-08-20 23:16 UTCEG score recompute
  40. 2026-08-20 23:16 UTCVendor advisory
  41. 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  42. 2026-08-20 10:09 UTCEG score recompute
  43. 2026-08-20 10:09 UTCVendor advisory
  44. 2026-08-19 17:03 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  45. 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  46. 2026-08-17 13:47 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  47. 2026-08-17 06:44 UTCVendor advisory
  48. 2026-08-16 16:52 UTCEG score recompute
  49. 2026-08-16 16:52 UTCVendor advisory
  50. 2026-08-16 14:56 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  51. 2026-08-16 03:55 UTCEG score recompute
  52. 2026-08-16 03:55 UTCVendor advisory
  53. 2026-08-16 02:14 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  54. 2026-08-15 14:58 UTCEG score recompute
  55. 2026-08-15 14:58 UTCVendor advisory
  56. 2026-08-15 01:30 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  57. 2026-08-15 01:10 UTCVendor advisory
  58. 2026-08-14 12:13 UTCVendor advisory
  59. 2026-08-13 23:15 UTCEG score recompute
  60. 2026-08-13 23:15 UTCVendor advisory
  61. 2026-08-13 22:00 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  62. 2026-08-13 02:47 UTCEG score recompute
  63. 2026-08-13 02:47 UTCVendor advisory
  64. 2026-08-12 13:51 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  65. 2026-08-12 13:50 UTCVendor advisory
  66. 2026-08-12 00:52 UTCEG score recompute
  67. 2026-08-12 00:52 UTCVendor advisory
  68. 2026-08-11 13:43 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  69. 2026-08-11 11:54 UTCEG score recompute
  70. 2026-08-11 11:54 UTCVendor advisory
  71. 2026-08-11 00:00 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  72. 2026-08-10 22:57 UTCVendor advisory
  73. 2026-08-10 06:04 UTCVendor advisory
  74. 2026-08-09 17:06 UTCEG score recompute
  75. 2026-08-09 17:06 UTCVendor advisory

Related CVEs(same product + same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-42211?
CVE-2026-42211 is a high-severity vulnerability; its CVE record was published on June 2, 2026. React Router is a router for React. In versions 7.0.0 through 7.14.1, when using Framework Mode, a combination of steps could potentially allow unauthorized remote code execution (RCE) through external requests. This attack requires the application code to have an existing prototype pollution…
When was the CVE record for CVE-2026-42211 published?
The CVE record for CVE-2026-42211 was published on June 2, 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 July 21, 2026; the record at its source may have been updated since.
Is CVE-2026-42211 actively exploited?
CVE-2026-42211 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.6% probability of exploitation in the next 30 days (49th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-42211?
CVE-2026-42211 has a CVSS base score of 8.1 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-42211?
A fix for CVE-2026-42211 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-42211 are linked in the Vendor Advisories panel on this page.

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