CVE-2026-6621

HIGHNVD 7.37.3—
EchelonGraph scoreMEDIUM confidence

Score 7.3 from GitHub Security Advisory published 2026-04-20. NVD baseline CVSS 7.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Elevated
7.3
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.3Exploit: NoneExposed: 0

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

A vulnerability was determined in 1024bit extend-deep up to 0.1.6. The impacted element is an unknown function of the file index.js. This manipulation of the argument __proto__ causes improperly controlled modification of object prototype attributes. Remote exploitation of the attack is possible. The exploit has been publicly disclosed and may be utilized. The code repository of the project has not been active for many years.

CVSS v3
7.3
EG Score
7.3(medium)
EPSS
25.7%
KEV
Not listed

Published

April 20, 2026

Last Modified

April 29, 2026

Advisory Details (1)

Auto-updated Jun 14, 2026
🔬 Proof of concept available. No patch confirmed yet.
generic🟡 PoC Available

security-research/extend-deep/prototype-pollution/PoC.md at main · sudo-secure/security-research · GitHub

https://github.com/sudo-secure/security-research/blob/main/extend-deep/prototype-pollution/PoC.md

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 9× in last 7d / 44× 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 114 total refreshes for this CVE.

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

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Frequently asked(5)

What is CVE-2026-6621?
CVE-2026-6621 is a high vulnerability published on April 20, 2026. A vulnerability was determined in 1024bit extend-deep up to 0.1.6. The impacted element is an unknown function of the file index.js. This manipulation of the argument proto causes improperly controlled modification of object prototype attributes. Remote exploitation of the attack is possible. The…
When was CVE-2026-6621 disclosed?
CVE-2026-6621 was first published in the National Vulnerability Database on April 20, 2026, with the most recent update on April 29, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-6621 actively exploited?
CVE-2026-6621 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 25.7% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-6621?
CVE-2026-6621 has a CVSS v3 base score of 7.3 (NVD).
How do I remediate CVE-2026-6621?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-6621, 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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