CVE-2021-23978 — CVE & Security Advisory Radar

🎯 CVE-2021-23978 🇪🇺 EUVD

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CVE-2021-23978 | Mozilla developers reported memory safety bugs present in Firefox 85 and Firefox ESR 78.7. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 86, Thunderbird < 78.8, and Firefox ESR < 78.8.

Mozilla developers reported memory safety bugs present in Firefox 85 and Firefox ESR 78.7. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 86, Thunderbird < 78.8, and Firefox ESR < 78.8.

Klassifikation & Betroffenheit:

Mozilla Firefox ESR < 78.8Thunderbird < 78.8Firefox < 86mozilla firefox *mozilla firefox_esr *mozilla thunderbird *debian debian_linux 9.0debian debian_linux 10.0

Improper Restriction of Operations within the Bounds of a Memory Buffer 🎯 High

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.

🛡️ Empfohlene Mitigation: Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow prot…

Vollständige Definition bei MITRE ➔

⚔️ Typische Angriffsmuster (CAPEC):

CAPEC-10 · Buffer Overflow via Environment Variable… (High) CAPEC-14 · Client-side Injection-induced Buffer Ove… (High) CAPEC-24 · Filter Failure through Buffer Overflow (High) CAPEC-42 · MIME Conversion (High) CAPEC-44 · Overflow Binary Resource File (Very High) CAPEC-45 · Buffer Overflow via Symbolic Links (High) CAPEC-100 · Overflow Buffers (Very High) CAPEC-123 · Buffer Manipulation (Very High)

🧩 Ähnliche Schwachstellen (Hersteller/Klasse/Score-Band):

CVE-2024-5022 4.4 CVE-2024-11692 4.3 CVE-2024-11701 4.3 CVE-2024-10941 4.3 CVE-2024-8388 4.3

📚 Referenzen & Quellen:

🇪🇺 Original-Eintrag (ENISA EUVD) 🇺🇸 NVD-Eintrag

Ausnutzungs-Zeitleiste:

Reserviert 2021

Veröffentlicht 02/2021

Heute 20.09.

Veröffentlicht:26.02.2021

Aktualisiert:17.06.2026 03:39

Assigner (CNA):mozilla

EUVD-ID:EUVD-2021-10899

Quellen: 🇪🇺 EUVD-Datenbank (ENISA) + 🇺🇸 NVD-Anreicherung · 24-h-Cache

CWE-119: Memory Corruption ✓ Offizieller Patch / Advisory verfügbar

💡 Gegenmaßnahme: Sicherheits-Update des Herstellers zeitnah einspielen und Netzwerksegmentierung prüfen.

Tier	2026-08-31	2026-09-19
≥90 %	0	538
≥50 %	0	1603
≥10 %	0	17
<10 %	300	56400

Datenquellen & Methodik: Primärquelle ist die EUVD der ENISA (laufender Datenbank-Sync, alle 15 Minuten), abgeglichen mit dem CISA-KEV-Katalog und der NVD — Detail-Dossiers reichern fehlende Felder live per NVD an — mit Fallback auf CIRCL vulnerability-lookup (EU/Non-Profit, aggregiert CVE-, GitHub- und OSV-Advisories). Der CISA-KEV-Katalog (Known Exploited Vulnerabilities, ~1.700 aktiv ausgenutzte Schwachstellen) wird bei jedem Sync vollständig neu geladen und kreuzreferenziert — filterbar über die KEV-Pille. CVSS 3.1 wird nach Ampel-Logik aus Verteidigersicht dekodiert; EPSS bezeichnet die 30-Tage-Exploit-Wahrscheinlichkeit (FIRST.org).

🇪🇺 ENISA EUVD 🇺🇸 NVD ⚠️ CISA KEV ⚡ EPSS

EPSS

1.5%

CVE-2021-23978 🌐 Netzwerk (Remote) 🔓 Keine Authentifizierung nötig

Mozilla

CVE-2021-23978 | Mozilla developers reported memory safety bugs present in Firefox 85 and Firefox ESR 78.7. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 86, Thunderbird < 78.8, and Firefox ESR < 78.8.

CWE-119: Memory Corruption ✓ Offizieller Patch / Advisory verfügbar

💡 Gegenmaßnahme: Sicherheits-Update des Herstellers zeitnah einspielen und Netzwerksegmentierung prüfen.

26.02.2021

🛡️ Details ➔

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