CVE-2020-15656

HIGHNVD 8.88.8—
EchelonGraph scoreMEDIUM confidence

Score 8.8 from GitHub Security Advisory (severity: HIGH) published 2022-05-24. NVD baseline CVSS 8.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
8.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 2%CVSS: 8.8Exploit: None knownExposed: 0

A fix is available — apply it.

JIT optimizations involving the Javascript arguments object could confuse later optimizations. This risk was already mitigated by various precautions in the code, resulting in this bug rated at only moderate severity. This vulnerability affects Firefox ESR < 78.1, Firefox < 79, and Thunderbird < 78.1.

CVSS v3
8.8
EG Score
8.8(medium)
EG Risk
45(Track)
EG Risk 45/100SSVC: Track

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
Severity88% × 45%
Exploitation2% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
2%
EPSS %ILE
72%
KEV
Not listed

Published

August 10, 2020

Last Modified

November 21, 2024

References (12)

Patch Availability(5)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntufirefox-mozsymbols (79.0+build1-0ubuntu0.20.04.1) @ focal2026-05-27ubuntu
redhatfirefox-0:78.3.0-1.el7_92020-09-30redhat
redhatfirefox-0:78.2.0-3.el8_02020-08-26redhat
redhatfirefox-0:78.2.0-3.el8_12020-08-26redhat
redhatfirefox-0:78.2.0-2.el8_22020-08-26redhat

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.

Weakness Classification(1)

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

All Vendor Advisories

(5)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 12× in last 7d / 45× 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 102 total refreshes for this CVE.

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

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Frequently asked(5)

What is CVE-2020-15656?
CVE-2020-15656 is a high vulnerability published on August 10, 2020. JIT optimizations involving the Javascript arguments object could confuse later optimizations. This risk was already mitigated by various precautions in the code, resulting in this bug rated at only moderate severity. This vulnerability affects Firefox ESR < 78.1, Firefox < 79, and Thunderbird <…
When was CVE-2020-15656 disclosed?
CVE-2020-15656 was first published in the National Vulnerability Database on August 10, 2020, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2020-15656 actively exploited?
CVE-2020-15656 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 2% probability of exploitation in the next 30 days, which ranks it in the top 28.2% of all scored CVEs.
What is the CVSS score of CVE-2020-15656?
CVE-2020-15656 has a CVSS v3 base score of 8.8 (NVD).
How do I remediate CVE-2020-15656?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2020-15656, 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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