CVE-2026-8657

HIGHPre-NVD 8.28.2—
EchelonGraph scoreMEDIUM confidence

Score 8.2 from GitHub Security Advisory (severity: HIGH) published 2026-05-16. the CNA's CVSS baseline 8.2; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:snyk, epss, ghsa
Trending — 3 sources updated this weekElevated
8.2EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.2Exploit: Elevated riskExposed: 0

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

Versions of the package jsondiffpatch before 0.7.6 are vulnerable to Prototype Pollution via the jsondiffpatch.patch() and jsondiffpatch/formatters/jsonpatch.patch() APIs. An attacker can perform prototype pollution by supplying crafted delta or JSON Patch documents, as attacker-controlled property names and path segments are used to traverse and modify objects without restricting access to special properties like __proto__ or constructor.prototype, allowing modification of Object.prototype.

CVSS v3
8.2
EG Score
8.2(medium)
EG Risk
68(Attend)
EG Risk 68/100SSVC: Attend

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
Severity82% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
0%
EPSS %ILE
31%
KEV
Not listed

Published

May 16, 2026

Last Modified

August 23, 2026

Advisory Details (3)

Auto-updated May 16, 2026
🔬 Proof of concept available. No patch confirmed yet.
generic🟡 PoC Available

Prototype Pollution in jsondiffpatch | CVE-2026-8657 | Snyk

https://security.snyk.io/vuln/SNYK-JS-JSONDIFFPATCH-16322990
generic

fix: prevent prototype pollution in patch, unpatch, reverse, and JSON… · benjamine/jsondiffpatch@381c012 · GitHub

https://github.com/benjamine/jsondiffpatch/commit/381c0125efab49f6f0dbc08317d01d55717672af
generic

Prototype Pollution in jsondiffpatch delta and JSON Patch application · GitHub

https://gist.github.com/yuki-matsuhashi/e570fb1579ae1f3190059b622b0473fb

Vendor Advisories for CVE-2026-8657(1)

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

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 12× in last 7d / 73× 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.

Showing the most recent 100 of 186 total refreshes for this CVE.

  1. 2026-08-26 14:47 UTCEPSS rescore
  2. 2026-08-25 13:49 UTCEPSS rescore
  3. 2026-08-24 14:18 UTCEPSS rescore
  4. 2026-08-23 15:36 UTCEG score recompute
  5. 2026-08-23 15:36 UTCGHSA enrichment
  6. 2026-08-23 00:19 UTCEPSS rescore
  7. 2026-08-22 01:14 UTCEG score recompute
  8. 2026-08-22 01:14 UTCGHSA enrichment
  9. 2026-08-21 23:49 UTCEPSS rescore
  10. 2026-08-20 22:56 UTCEPSS rescore
  11. 2026-08-20 19:15 UTCEG score recompute
  12. 2026-08-20 19:15 UTCGHSA enrichment
  13. 2026-08-19 17:04 UTCEPSS rescore
  14. 2026-08-18 13:49 UTCEPSS rescore
  15. 2026-08-18 13:49 UTCEPSS rescore
  16. 2026-08-17 13:47 UTCEPSS rescore
  17. 2026-08-17 10:12 UTCEG score recompute
  18. 2026-08-17 10:12 UTCGHSA enrichment
  19. 2026-08-16 14:56 UTCEPSS rescore
  20. 2026-08-16 14:56 UTCEPSS rescore
  21. 2026-08-16 03:44 UTCEG score recompute
  22. 2026-08-16 03:44 UTCGHSA enrichment
  23. 2026-08-16 02:15 UTCEPSS rescore
  24. 2026-08-15 01:31 UTCEPSS rescore
  25. 2026-08-14 18:00 UTCGHSA enrichment
Show 75 more
  1. 2026-08-14 04:39 UTCEG score recompute
  2. 2026-08-14 04:39 UTCGHSA enrichment
  3. 2026-08-13 22:00 UTCEPSS rescore
  4. 2026-08-13 15:35 UTCGHSA enrichment
  5. 2026-08-13 03:48 UTCGHSA enrichment
  6. 2026-08-12 14:44 UTCEG score recompute
  7. 2026-08-12 14:44 UTCGHSA enrichment
  8. 2026-08-12 13:51 UTCEPSS rescore
  9. 2026-08-11 13:59 UTCEG score recompute
  10. 2026-08-11 13:59 UTCGHSA enrichment
  11. 2026-08-11 13:43 UTCEPSS rescore
  12. 2026-08-11 00:46 UTCEG score recompute
  13. 2026-08-11 00:46 UTCGHSA enrichment
  14. 2026-08-11 00:00 UTCEPSS rescore
  15. 2026-08-10 03:51 UTCGHSA enrichment
  16. 2026-08-09 14:47 UTCEG score recompute
  17. 2026-08-09 14:47 UTCGHSA enrichment
  18. 2026-08-09 13:47 UTCEPSS rescore
  19. 2026-08-09 01:43 UTCEG score recompute
  20. 2026-08-09 01:43 UTCGHSA enrichment
  21. 2026-08-08 16:37 UTCEPSS rescore
  22. 2026-08-08 03:24 UTCEG score recompute
  23. 2026-08-08 03:24 UTCGHSA enrichment
  24. 2026-08-07 16:30 UTCEPSS rescore
  25. 2026-08-07 14:20 UTCGHSA enrichment
  26. 2026-08-07 01:16 UTCEG score recompute
  27. 2026-08-07 01:16 UTCGHSA enrichment
  28. 2026-08-06 13:47 UTCEPSS rescore
  29. 2026-08-06 10:34 UTCGHSA enrichment
  30. 2026-08-05 21:28 UTCEG score recompute
  31. 2026-08-05 21:28 UTCGHSA enrichment
  32. 2026-08-05 19:17 UTCEPSS rescore
  33. 2026-08-05 19:17 UTCEPSS rescore
  34. 2026-08-04 15:10 UTCEPSS rescore
  35. 2026-08-04 10:39 UTCEPSS rescore
  36. 2026-08-03 18:53 UTCEG score recompute
  37. 2026-08-03 18:53 UTCGHSA enrichment
  38. 2026-08-03 10:36 UTCEPSS rescore
  39. 2026-08-02 20:57 UTCGHSA enrichment
  40. 2026-08-02 07:53 UTCEG score recompute
  41. 2026-08-02 07:53 UTCGHSA enrichment
  42. 2026-08-02 02:27 UTCEPSS rescore
  43. 2026-08-01 18:47 UTCEG score recompute
  44. 2026-08-01 18:47 UTCGHSA enrichment
  45. 2026-08-01 04:16 UTCEPSS rescore
  46. 2026-07-30 16:28 UTCEPSS rescore
  47. 2026-07-30 01:30 UTCEPSS rescore
  48. 2026-07-28 15:37 UTCEPSS rescore
  49. 2026-07-27 14:14 UTCEPSS rescore
  50. 2026-07-26 14:54 UTCEPSS rescore
  51. 2026-07-25 14:18 UTCEPSS rescore
  52. 2026-07-24 14:18 UTCEPSS rescore
  53. 2026-07-23 03:23 UTCEG score recompute
  54. 2026-07-22 14:08 UTCEPSS rescore
  55. 2026-07-21 15:25 UTCEPSS rescore
  56. 2026-07-21 15:25 UTCEPSS rescore
  57. 2026-07-20 17:08 UTCEPSS rescore
  58. 2026-07-19 14:31 UTCEPSS rescore
  59. 2026-07-19 02:29 UTCEPSS rescore
  60. 2026-07-18 15:44 UTCMITRE cvelistV5CVSS v4 → 8.8
  61. 2026-07-18 10:04 UTCEPSS rescore
  62. 2026-07-18 00:29 UTCOSV refresh
  63. 2026-07-16 17:03 UTCEPSS rescore
  64. 2026-07-15 16:57 UTCEPSS rescore
  65. 2026-07-15 02:00 UTCEPSS rescore
  66. 2026-07-13 22:31 UTCEPSS rescore
  67. 2026-07-13 06:13 UTCEPSS rescore
  68. 2026-07-12 05:46 UTCEPSS rescore
  69. 2026-07-11 08:27 UTCEPSS rescore
  70. 2026-07-09 19:10 UTCEPSS rescore
  71. 2026-07-08 15:16 UTCEPSS rescore
  72. 2026-07-07 13:46 UTCEPSS rescore
  73. 2026-07-06 16:27 UTCEPSS rescore
  74. 2026-07-06 16:27 UTCEPSS rescore
  75. 2026-07-06 02:23 UTCEPSS rescore

Frequently asked(5)

What is CVE-2026-8657?
CVE-2026-8657 is a high vulnerability published on May 16, 2026. Versions of the package jsondiffpatch before 0.7.6 are vulnerable to Prototype Pollution via the jsondiffpatch.patch() and jsondiffpatch/formatters/jsonpatch.patch() APIs. An attacker can perform prototype pollution by supplying crafted delta or JSON Patch documents, as attacker-controlled property…
When was CVE-2026-8657 disclosed?
CVE-2026-8657 was first published in the National Vulnerability Database on May 16, 2026, with the most recent update on August 23, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-8657 actively exploited?
CVE-2026-8657 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 69.3% of all scored CVEs.
What is the CVSS score of CVE-2026-8657?
CVE-2026-8657 has a CVSS v4.0 base score of 8.2 (CNA self-assessment; NVD's own analysis pending).
How do I remediate CVE-2026-8657?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-8657, 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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