CVE-2026-76641 — CVE & Security Advisory Radar

🎯 CVE-2026-76641 🧪 PoC 🇪🇺 EUVD

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CVE-2026-76641 | Expat through 2.8.3 contains an out-of-bounds read vulnerability that allows attackers to trigger memory corruption by processing XML with external entity parsers created via XML_ExternalEntityParserCreate. A struct size mismatch between ELEMENT_TYPE members causes storeAtts to read the attIndex member past allocated memory boundaries, resulting in failure to normalize whitespace in non-CDATA attributes or a wild pointer dereference causing a segfault. This v

Expat through 2.8.3 contains an out-of-bounds read vulnerability that allows attackers to trigger memory corruption by processing XML with external entity parsers created via XML_ExternalEntityParserCreate. A struct size mismatch between ELEMENT_TYPE members causes storeAtts to read the attIndex member past allocated memory boundaries, resulting in failure to normalize whitespace in non-CDATA attributes or a wild pointer dereference causing a segfault. This vulnerability was introduced by the fix for CVE-2026-66046.

Klassifikation & Betroffenheit:

libexpat libexpat 0 ≤2.8.3

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-2026-93990 8.7

🩹 Patch verfügbar (OSV):

🩹 92810461043fce37e70079b37ab1f04490a8f039 (Commit) 🩹 98599f6dcc2b460410881fe420f5f55d6bec63bf (Commit)

📚 Referenzen & Quellen:

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

Ausnutzungs-Zeitleiste:

Reserviert 2026

Veröffentlicht 08/2026

Heute 22.09.

CVSS-Vektor-Analyse: 8.7

AV · Angriffsvektor Netzwerk

AC · Komplexität Gering

PR · Privilegien Keine

UI · Interaktion Keine

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Veröffentlicht:20.08.2026

Aktualisiert:20.08.2026 19:17

Assigner (CNA):VulnCheck

EUVD-ID:EUVD-2026-63493

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	2026-09-04	2026-09-21
≥90 %	0	488
≥50 %	0	1471
≥10 %	0	7
<10 %	300	0

EPSS

0.4%

CVE-2026-76641 🌐 Netzwerk (Remote) 🔓 Keine Authentifizierung nötig

libexpat

CVE-2026-76641 | Expat through 2.8.3 contains an out-of-bounds read vulnerability that allows attackers to trigger memory corruption by processing XML with external entity parsers created via XML_ExternalEntityParserCreate. A struct size mismatch between ELEMENT_TYPE members causes storeAtts to read the attIndex member past allocated memory boundaries, resulting in failure to normalize whitespace in non-CDATA attributes or a wild pointer dereference causing a segfault. This v

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

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

20.08.2026

🛡️ Details ➔

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