CVE-2021-29978

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.8 under NVD CVSS v3. EPSS exploit probability: 2.8% (85th percentile of EPSS-scored CVEs). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 2.8%CVSS: 9.8Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Multiple low security issues were discovered and fixed in a security audit of Mozilla VPN 2.x branch as part of a 3rd party security audit. This vulnerability affects Mozilla VPN < 2.3.

CVSS v3
9.8
EG Score
9.8CRITICALmedium confidence
EG Risk
50
EG Risk 50/100CISA SSVC

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%
Exploitation3% × 40%
Automatability30% × 15%
CISA SSVC: Track at low or medium mission impact; Track* or Attend at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
2.8%
EPSS %ILE
85th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track* or Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (no KEV listing, exploit record or EPSS ≥ 50%) · Automatable unknown (not published for this CVE) · Technical impact total (CVSS ≥ 9.0). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

August 5, 2021

Last Modified

November 21, 2024

Advisory Details (10)

Auto-updated Oct 4, 2026
Patch available.
generic

FVP-02-012 WP5: Unencrypted shared preferences · Issue #808 · mozilla-mobile/mozilla-vpn-client · GitHub

https://github.com/mozilla-mobile/mozilla-vpn-client/issues/808
generic

FVP-02-011 API: Information disclosure via device endpoint · Issue #806 · mozilla-mobile/mozilla-vpn-client · GitHub

https://github.com/mozilla-mobile/mozilla-vpn-client/issues/806
generic

FVP-02-010 WP5: Android app supports insecure v1 signature · Issue #805 · mozilla-mobile/mozilla-vpn-client · GitHub

https://github.com/mozilla-mobile/mozilla-vpn-client/issues/805
generic

FVP-02-009 WP5: Secure flag missing on views for Android app · Issue #804 · mozilla-mobile/mozilla-vpn-client · GitHub

https://github.com/mozilla-mobile/mozilla-vpn-client/issues/804
generic

FVP-02-008 WP5: Android app allows backups of application data · Issue #803 · mozilla-mobile/mozilla-vpn-client · GitHub

https://github.com/mozilla-mobile/mozilla-vpn-client/issues/803
generic

FVP-02-006 WP3: Race condition in Ping Sender could expose gateway IP · Issue #801 · mozilla-mobile/mozilla-vpn-client · GitHub

https://github.com/mozilla-mobile/mozilla-vpn-client/issues/801
generic

FVP-02-005 WP1-3: Authenticationlistener allows disturbance of login · Issue #800 · mozilla-mobile/mozilla-vpn-client · GitHub

https://github.com/mozilla-mobile/mozilla-vpn-client/issues/800
generic

FVP-02-004 WP4: ATS policy unnecessarily weakened · Issue #799 · mozilla-mobile/mozilla-vpn-client · GitHub

https://github.com/mozilla-mobile/mozilla-vpn-client/issues/799
generic

FVP-02-003 General: Balrog incorrectly verifies certificate chain · Issue #798 · mozilla-mobile/mozilla-vpn-client · GitHub

https://github.com/mozilla-mobile/mozilla-vpn-client/issues/798
generic

FVP-02-002 WP1: Balrog does not verify certificate chain on macOS · Issue #797 · mozilla-mobile/mozilla-vpn-client · GitHub

https://github.com/mozilla-mobile/mozilla-vpn-client/issues/797

Data Freshness Timeline

(refreshed 8× in last 7d / 32× 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 182 total refreshes for this CVE.

  1. 2026-10-05 17:40 UTCEPSS rescore
  2. 2026-10-03 14:22 UTCEPSS rescore
  3. 2026-10-03 14:22 UTCEPSS rescore
  4. 2026-10-02 16:22 UTCEPSS rescore
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  6. 2026-09-30 15:34 UTCEG score recompute
  7. 2026-09-30 15:00 UTCEPSS rescore
  8. 2026-09-29 15:15 UTCEPSS rescore
  9. 2026-09-28 13:47 UTCEPSS rescore
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  14. 2026-09-25 20:45 UTCOSV refresh
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  1. 2026-09-12 14:57 UTCEPSS rescore
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  5. 2026-09-07 15:58 UTCEPSS rescore
  6. 2026-09-06 13:44 UTCEPSS rescore
  7. 2026-09-06 11:00 UTCOSV refresh
  8. 2026-09-05 15:25 UTCEPSS rescore
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  24. 2026-08-20 22:52 UTCEPSS rescore
  25. 2026-08-19 21:34 UTCOSV refresh
  26. 2026-08-19 17:01 UTCEPSS rescore
  27. 2026-08-18 13:45 UTCEPSS rescore
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  40. 2026-08-05 19:14 UTCEPSS rescore
  41. 2026-08-04 16:57 UTCOSV refresh
  42. 2026-08-04 15:06 UTCEPSS rescore
  43. 2026-08-04 10:34 UTCEPSS rescore
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  56. 2026-07-23 14:16 UTCEPSS rescore
  57. 2026-07-23 02:00 UTCEG score recompute
  58. 2026-07-22 22:47 UTCEG score recompute
  59. 2026-07-22 14:06 UTCEPSS rescore
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  61. 2026-07-21 15:22 UTCEPSS rescore
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  63. 2026-07-20 17:05 UTCEPSS rescore
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  65. 2026-07-19 02:27 UTCEPSS rescore
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  67. 2026-07-18 14:59 UTCOSV refresh
  68. 2026-07-18 10:02 UTCEPSS rescore
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  70. 2026-07-16 17:00 UTCEPSS rescore
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  74. 2026-07-13 22:27 UTCEPSS rescore
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Frequently asked(5)

What is CVE-2021-29978?
CVE-2021-29978 is a critical vulnerability published on August 5, 2021. Multiple low security issues were discovered and fixed in a security audit of Mozilla VPN 2.x branch as part of a 3rd party security audit. This vulnerability affects Mozilla VPN < 2.3.
When was CVE-2021-29978 disclosed?
CVE-2021-29978 was first published on August 5, 2021, 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-2021-29978 actively exploited?
CVE-2021-29978 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 2.8% probability of exploitation in the next 30 days (85th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2021-29978?
CVE-2021-29978 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2021-29978?
A fix for CVE-2021-29978 is available: update to the fixed version the vendor names in its advisory.

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