CVE-2021-1871

CRITICALNVD 9.89.8—
EchelonGraph scoreHIGH confidence

Score elevated to 9.8 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 9.8 retained for reference. Confidence: HIGH.

Triggered by: CISA KEV (actively exploited)
Sources: cisa_kev, epss, ghsa, nvd
Trending — 5 sources updated this weekExploited in the wild
9.8
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV)
CISA-KEV: ExploitedEPSS: 7%CVSS: 9.8Exploit: NoneExposed: 0

A fix is available — apply it.

A logic issue was addressed with improved restrictions. This issue is fixed in macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave, iOS 14.4 and iPadOS 14.4. A remote attacker may be able to cause arbitrary code execution. Apple is aware of a report that this issue may have been actively exploited..

CVSS v3
9.8
EG Score
9.8(high)
EG Risk
99(Act)
EG Risk 99/100SSVC: Act

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
Severity98% × 45%
Exploitation100% × 40%
Automatability100% × 15%
Action: Fix now — active exploitation, automatable, high impact.
EPSS
93.6%
KEV
⚠ Exploited

Published

April 2, 2021

Last Modified

October 23, 2025

Advisory Details (5)

Auto-updated May 31, 2026
⚠️ Active exploitation confirmed. Patch available. Sources: cisa.
cisa Patch Available🔴 Active Exploitation

Known Exploited Vulnerabilities Catalog | CISA

Known Exploited Vulnerabilities Catalog | CISA. Listed in CISA Known Exploited Vulnerabilities catalog.

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-1871
generic

[SECURITY] [DSA 4923-1] webkit2gtk security update

https://www.debian.org/security/2021/dsa-4923
generic🔴 Active Exploitation

About the security content of macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave - Apple Support

https://support.apple.com/en-us/HT212147
generic🔴 Active Exploitation

About the security content of iOS 14.4 and iPadOS 14.4 - Apple Support

https://support.apple.com/en-us/HT212146
generic

[SECURITY] Fedora 33 Update: webkit2gtk3-2.32.0-1.fc33 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/L3L6ZZOU5JS7E3RFYGLP7UFLXCG7TNLU/

Vendor Advisories for CVE-2021-1871(2)

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

Patch Availability(3)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntuwebkit2gtk-driver (2.32.0-0ubuntu0.18.04.1) @ bionic2026-07-22ubuntu
redhatwebkitgtk4-0:2.48.3-2.el7_92025-07-07redhat
redhatwebkit2gtk3-0:2.32.3-2.el82021-11-09redhat

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.

Additional Vendor Advisories

(1)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 107× in last 7d / 453× 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 815 total refreshes for this CVE.

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

Related CVEs(same vendor)

Frequently asked(6)

What is CVE-2021-1871?
CVE-2021-1871 is a critical vulnerability published on April 2, 2021. A logic issue was addressed with improved restrictions. This issue is fixed in macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave, iOS 14.4 and iPadOS 14.4. A remote attacker may be able to cause arbitrary code execution. Apple is aware of a report that this…
When was CVE-2021-1871 disclosed?
CVE-2021-1871 was first published in the National Vulnerability Database on April 2, 2021, with the most recent update on October 23, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-1871 actively exploited?
Yes. CISA added CVE-2021-1871 to the Known Exploited Vulnerabilities catalog on November 3, 2021, affecting Apple iOS, iPadOS, and macOS. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.
What is the CVSS score of CVE-2021-1871?
CVE-2021-1871 has a CVSS v3 base score of 9.8 (NVD).
Which products are affected by CVE-2021-1871?
CVE-2021-1871 affects Apple iOS, iPadOS, and macOS. 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-2021-1871?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-1871, 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.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2021-1871

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