CVE-2026-42007 — CVE & Security Advisory Radar

🎯 CVE-2026-42007 CRITICAL 9.1 🔥 EPSS 73.8% 🇪🇺 EUVD

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CVE-2026-42007 | An attacker that has valid credentials can use a Sieve script with the editheader extension to trigger a use-after-free in the mail editing code, and to write memory contents beyond the intended buffer into the delivered mail. This causes memory leak and opportunity to do memory corruption during mail delivery, which can crash the delivery process and may allow execution of arbitrary code in the context of that process. Disable the Sieve editheader extension.

An attacker that has valid credentials can use a Sieve script with the editheader extension to trigger a use-after-free in the mail editing code, and to write memory contents beyond the intended buffer into the delivered mail. This causes memory leak and opportunity to do memory corruption during mail delivery, which can crash the delivery process and may allow execution of arbitrary code in the context of that process. Disable the Sieve editheader extension. Update to non-vulnerable version. No publicly available exploits are known.

Klassifikation & Betroffenheit:

Open-Xchange GmbH OX Dovecot Pro 2.3.0 <2.3.22.2OX Dovecot Pro 3.1.0 <3.1.6OX Dovecot Pro 3.0.0 <3.0.7OX Dovecot CE 2.3.0 <2.4.5

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-2023-29048 8.8 CVE-2023-29051 8.1 CVE-2026-24031 7.7 CVE-2023-29050 7.6

📚 Referenzen & Quellen:

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

🔗 documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxd…

Ausnutzungs-Zeitleiste:

Reserviert 2026

Veröffentlicht 08/2026

Heute 02.09.

CVSS-Vektor-Analyse: 9.1

AV · Angriffsvektor Netzwerk

AC · Komplexität Gering

PR · Privilegien Gering

UI · Interaktion Keine

S · Scope Verändert

C · Vertraulichkeit Gering

I · Integrität Gering

A · Verfügbarkeit Hoch

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:H

Veröffentlicht:28.08.2026

Aktualisiert:28.08.2026 20:17

Assigner (CNA):OX

EUVD-ID:EUVD-2026-67672

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	2026-08-29	2026-09-02
≥90 %	4	0
≥50 %	4	0
≥10 %	3	0
<10 %	304	300

9.1 CRITICAL

🇪🇺 EUVD

EPSS

73.8%

CVE-2026-42007 🌐 Netzwerk (Remote) 🔑 Geringe Nutzerrechte nötig

Open-Xchange GmbH

CVE-2026-42007 | An attacker that has valid credentials can use a Sieve script with the editheader extension to trigger a use-after-free in the mail editing code, and to write memory contents beyond the intended buffer into the delivered mail. This causes memory leak and opportunity to do memory corruption during mail delivery, which can crash the delivery process and may allow execution of arbitrary code in the context of that process. Disable the Sieve editheader extension.

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

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

28.08.2026

🛡️ Details ➔

Zero-Day & Vulnerability Intelligence Hub