CVE-2020-27950

CRITICALNVD 5.59.0▲
EchelonGraph scoreHIGH confidence

Score elevated to 9.0 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03), indicating real-world exploitation has been confirmed by US federal agencies. NVD baseline CVSS 5.5 retained for reference. Confidence: HIGH.

Triggered by: CISA KEV (actively exploited)
Sources: cisa_kev, epss, ghsa, nvd
Trending — 4 sources updated this weekExploited in the wild
9.0EG
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV)
CISA-KEV: ExploitedEPSS PROB: 17%CVSS: 5.5Exploit: cisa kev · ssvc active · epss top5pct · public exploitExposed: 0

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

A memory initialization issue was addressed. This issue is fixed in macOS Big Sur 11.0.1, watchOS 7.1, iOS 12.4.9, watchOS 6.2.9, Security Update 2020-006 High Sierra, Security Update 2020-006 Mojave, iOS 14.2 and iPadOS 14.2, watchOS 5.3.9, macOS Catalina 10.15.7 Supplemental Update, macOS Catalina 10.15.7 Update. A malicious application may be able to disclose kernel memory.

CVSS v3
5.5
EG Score
9.0(high)
EG Risk
81(Attend)
EG Risk 81/100SSVC: 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
Severity90% × 45%
Exploitation100% × 40%
Automatability0% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
17%
EPSS %ILE
97%
KEV
⚠ Exploited

Published

December 8, 2020

Last Modified

October 27, 2025

Advisory Details (10)

Auto-updated Jun 13, 2026
⚠️ Active exploitation confirmed. No patch confirmed yet.
generic🔴 Active Exploitation

About the security content of macOS Catalina 10.15.7 Supplemental Update, macOS Catalina 10.15.7 Update - Apple Support

https://support.apple.com/en-us/HT211947
generic🔴 Active Exploitation

About the security content of Security Update 2020-006 High Sierra, Security Update 2020-006 Mojave - Apple Support

https://support.apple.com/en-us/HT211946
generic🔴 Active Exploitation

About the security content of watchOS 5.3.9 - Apple Support

https://support.apple.com/en-us/HT211945
generic🔴 Active Exploitation

About the security content of watchOS 6.2.9 - Apple Support

https://support.apple.com/en-us/HT211944
generic🔴 Active Exploitation

About the security content of iOS 12.4.9 - Apple Support

https://support.apple.com/en-us/HT211940
generic🔴 Active Exploitation

About the security content of macOS Big Sur 11.0.1 - Apple Support

https://support.apple.com/en-us/HT211931
generic🔴 Active Exploitation

About the security content of iOS 14.2 and iPadOS 14.2 - Apple Support

https://support.apple.com/en-us/HT211929
generic🔴 Active Exploitation

About the security content of watchOS 7.1 - Apple Support

https://support.apple.com/en-us/HT211928
generic🔴 Active Exploitation

Full Disclosure: APPLE-SA-2020-12-14-4 Additional information for APPLE-SA-2020-11-13-1 macOS Big Sur 11.0.1

http://seclists.org/fulldisclosure/2020/Dec/32
generic

Packet Storm

http://packetstormsecurity.com/files/161296/XNU-Kernel-Mach-Message-Trailers-Memory-Disclosure.html

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 60× in last 7d / 253× 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 909 total refreshes for this CVE.

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

Publicly available exploits

(2 references)

Working exploit code is in the public domain (2 GitHub PoCs). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoClyonzon2/browser-crash-tool
    First seen Sep 15, 2024

    A Bash script for Kali Linux that exploits an iOS WebKit vulnerability (CVE-2020-27950) using Metasploit and ngrok. Automates payload delivery with a public URL via ngrok, checks for required tools, handles errors, and provides an easy way to crash browsers for educational purposes only.

    Open source ↗
  • GitHub PoCsynacktiv/CVE-2020-27950
    First seen Dec 1, 2020

    CVE-2020-27950 exploit

    Open source ↗

Frequently asked(6)

What is CVE-2020-27950?
CVE-2020-27950 is a critical vulnerability published on December 8, 2020. A memory initialization issue was addressed. This issue is fixed in macOS Big Sur 11.0.1, watchOS 7.1, iOS 12.4.9, watchOS 6.2.9, Security Update 2020-006 High Sierra, Security Update 2020-006 Mojave, iOS 14.2 and iPadOS 14.2, watchOS 5.3.9, macOS Catalina 10.15.7 Supplemental Update, macOS…
When was CVE-2020-27950 disclosed?
CVE-2020-27950 was first published in the National Vulnerability Database on December 8, 2020, with the most recent update on October 27, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2020-27950 actively exploited?
Yes. CISA added CVE-2020-27950 to the Known Exploited Vulnerabilities catalog on November 3, 2021, affecting Apple Multiple Products. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.
What is the CVSS score of CVE-2020-27950?
CVE-2020-27950 has a CVSS v3 base score of 5.5 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.0.
Which products are affected by CVE-2020-27950?
CVE-2020-27950 affects Apple Multiple Products. The full affected-products list, including version ranges and fixed versions, is shown in the Affected Packages section of this page.
How do I remediate CVE-2020-27950?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2020-27950, 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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