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
Elevated
8.2EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.7%CVSS: 8.2Exploit: Elevated riskExposed services: Not assessed

A fix is available — apply it.

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
8.2HIGHmedium confidence
EG Risk
68
EG Risk 68/100

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%
EPSS PROB
0.7%
EPSS %ILE
50th
KEV
Not listed

Published

May 16, 2026

Last Modified

August 23, 2026

Advisory Details (3)

Auto-updated May 16, 2026
🔬 Proof of concept available. Patch available.
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.

Affected Packages

(1 across 1 ecosystem)
npm(1)
PackageVulnerable rangeFix by version rangeDependents
jsondiffpatch—
  • every version up to 0.7.6: fixed in 0.7.6
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 7× in last 7d / 28× 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 226 total refreshes for this CVE.

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

Related CVEs(same product + same CWE)

Same product

1 shown

npm:jsondiffpatch

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 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 0.7% probability of exploitation in the next 30 days (50th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-8657?
CVE-2026-8657 has a CVSS base score of 8.2 (the CNA's own assessment, by snyk; NVD's own analysis pending).
How do I remediate CVE-2026-8657?
A fix for CVE-2026-8657 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-8657 are linked in the Vendor Advisories panel on this page.

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