CVE-2026-59952

MEDIUMPre-NVD 6.96.9
EchelonGraph scoreMEDIUM confidence

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

This medium-severity CVE scores 6.9 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4% (32nd 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
Elevated

Also known asEUVD-2026-50775 (ENISA EUVD) · GHSA-5qjj-4xww-7phc (GitHub Security Advisories)Source: ENISA EUVD

6.9EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 6.9Exploit: No code on recordExposed services: Not assessed

A fix is available — apply it.

Valibot helps validate data using a schema. Versions prior to 1.4.2 can throw a TypeError inside its flatten() helper when validation issues contain attacker-controlled object keys such as toString, valueOf, or hasOwnProperty. The issue is reachable through normal record() validation. record() intentionally filters __proto__, prototype, and constructor, but it still accepts other own keys that collide with inherited Object.prototype properties. If the record key schema or value schema rejects such an entry, Valibot creates an issue path containing that key. Passing the resulting issues to Valibot's documented flatten() helper causes flatErrors.nested[dotPath] to resolve to the inherited method instead of an own error array, and the helper calls .push(...) on that function. This is not a global prototype pollution issue. The impact is availability/error handling: applications that validate user-controlled objects with record() and flatten validation errors for API responses can crash the request path with a TypeError instead of returning structured validation errors. This issue has been fixed in version 1.4.2.

CVSS
6.9
EG Score
6.9MEDIUMmedium confidence
EG Risk
62
EG Risk 62/100

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)
Severity69% × 45%
Impact severity (EG Severity): CVSS 6.9 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation public PoC (CISA Vulnrichment) · Automatable yes (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 at low or medium mission impact and sooner than that at high.
EPSS PROB
0.4%
EPSS %ILE
32nd
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 (6.9): severity, escalated by confirmed exploitation. This CVE's 6.9 is its impact severity (EG Severity), not escalated.

EG Severity
6.9 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.a secondary CVSS source
EG Likelihood
0.4% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-31). 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; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation public PoC (CISA Vulnrichment) · Automatable yes (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)14 days if the affected system is publicly exposed; 60 days if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (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

July 24, 2026

Last Modified

October 23, 2026

Advisory Details (4)

Auto-updated Jul 30, 2026
Patch available. Sources: github_release, github, github_pr, github_commit.
GitHub release Patch Available

v1.4.2

Patch available: open-circle/valibot v1.4.2

https://github.com/open-circle/valibot/releases/tag/v1.4.2
GitHub commit Patch Available

commit 1bd01c304657 (open-circle/valibot)

Patch available: open-circle/valibot v1.4.2 (contains commit 1bd01c304657)

https://github.com/open-circle/valibot/commit/1bd01c304657cd0809cc92694360b6cc60f700bf
GitHub pull request Patch Available

fix: handle keys that collide with Object.prototype in flatten and merge

Patch available: open-circle/valibot v1.4.2 (PR #1522 merged 2026-06-28)

https://github.com/open-circle/valibot/pull/1522
GitHub advisoryMentions a patch (unverified)

record() issue paths can make flatten() throw for inherited Object property names · Advisory · open-circle/valibot · GitHub

https://github.com/open-circle/valibot/security/advisories/GHSA-5qjj-4xww-7phc

Vendor Advisories for CVE-2026-59952(1)

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

Patch Availability(1)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
npmvalibot @ 1.4.2 (fixes <= 1.4.1)—ghsa

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
valibot—
  • every version up to 1.4.2: fixed in 1.4.2
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 7× 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 its CVE.org record (CNA or CISA ADP). An arrow marks a change the record states ("CVSS → 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). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.

Showing the most recent 100 of 163 rows 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 63 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-13 16:53 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  2. 2026-11-12 16:34 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  3. 2026-11-11 16:40 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  4. 2026-11-10 16:44 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  5. 2026-11-09 16:35 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  6. 2026-11-08 16:40 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  7. 2026-11-07 16:39 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  8. 2026-11-06 16:38 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  9. 2026-11-05 16:38 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  10. 2026-11-04 16:36 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  11. 2026-11-03 16:48 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  12. 2026-11-02 16:45 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  13. 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  14. 2026-11-01 07:41 UTCGHSA enrichmentGHSA-5qjj-4xww-7phc · GitHub severity MODERATE
  15. 2026-11-01 07:41 UTCEchelonGraph re-scored
  16. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  17. 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  18. 2026-10-29 16:39 UTCEchelonGraph re-scored
  19. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  20. 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  21. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  22. 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  23. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  24. 2026-10-25 14:16 UTCEchelonGraph re-scored
  25. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
Show 75 more
  1. 2026-10-23 22:31 UTCEchelonGraph re-scored
  2. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  3. 2026-10-22 20:55 UTCEchelonGraph re-scored
  4. 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  5. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  6. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  7. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  8. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  9. 2026-10-18 03:26 UTCEchelonGraph re-scored
  10. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  11. 2026-10-16 16:43 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  12. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  13. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  14. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  15. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  16. 2026-10-12 15:52 UTCEchelonGraph re-scored
  17. 2026-10-11 19:36 UTCEchelonGraph re-scored
  18. 2026-10-11 16:51 UTCEchelonGraph re-scored
  19. 2026-10-11 14:13 UTCEchelonGraph re-scored
  20. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  21. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  22. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  23. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  24. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  25. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  26. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  27. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  28. 2026-10-04 07:42 UTCEchelonGraph re-scored
  29. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  30. 2026-10-03 03:18 UTCEchelonGraph re-scored
  31. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  32. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  33. 2026-10-01 05:59 UTCEchelonGraph re-scored
  34. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  35. 2026-09-29 15:22 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  36. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  37. 2026-09-28 04:27 UTCEchelonGraph re-scored
  38. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  39. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  40. 2026-09-25 10:07 UTCEchelonGraph re-scored
  41. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  42. 2026-09-23 22:17 UTCEchelonGraph re-scored
  43. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  44. 2026-09-22 22:13 UTCEchelonGraph re-scored
  45. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  46. 2026-09-20 01:40 UTCEchelonGraph re-scored
  47. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  48. 2026-09-18 08:39 UTCEchelonGraph re-scored
  49. 2026-09-17 19:31 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  50. 2026-09-17 10:14 UTCEchelonGraph re-scored
  51. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  52. 2026-09-16 11:59 UTCEchelonGraph re-scored
  53. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  54. 2026-09-15 09:38 UTCEchelonGraph re-scored
  55. 2026-09-15 03:11 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  56. 2026-09-14 11:23 UTCEchelonGraph re-scored
  57. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  58. 2026-09-13 13:07 UTCEchelonGraph re-scored
  59. 2026-09-11 16:36 UTCEchelonGraph re-scored
  60. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  61. 2026-09-10 13:36 UTCEchelonGraph re-scored
  62. 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  63. 2026-09-09 08:45 UTCEchelonGraph re-scored
  64. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  65. 2026-09-06 17:38 UTCEchelonGraph re-scored
  66. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  67. 2026-09-05 19:23 UTCEchelonGraph re-scored
  68. 2026-09-04 12:51 UTCEchelonGraph re-scored
  69. 2026-09-04 05:07 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  70. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  71. 2026-09-01 23:16 UTCEchelonGraph re-scored
  72. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  73. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  74. 2026-08-30 22:32 UTCEchelonGraph re-scored
  75. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.3% · 22nd percentile

Frequently asked(5)

What is CVE-2026-59952?
CVE-2026-59952 is a medium-severity vulnerability; its CVE record was published on July 24, 2026. Valibot helps validate data using a schema. Versions prior to 1.4.2 can throw a TypeError inside its flatten() helper when validation issues contain attacker-controlled object keys such as toString, valueOf, or hasOwnProperty. The issue is reachable through normal record() validation. record()…
When was the CVE record for CVE-2026-59952 published?
The CVE record for CVE-2026-59952 was published on July 24, 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 October 23, 2026; the record at its source may have been updated since.
Is CVE-2026-59952 actively exploited?
CVE-2026-59952 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (32nd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-59952?
CVE-2026-59952 has a CVSS base score of 6.9 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-59952?
A fix for CVE-2026-59952 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-59952 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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