CVE-2026-92707

{"id": "CVE-2026-92707", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-92707", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-10-15T20:10:28.719217Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "security-advisories@github.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 5.3, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "LOW", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 1.4, "exploitabilityScore": 3.9}]}, "affected": [{"source": "security-advisories@github.com", "affectedData": [{"vendor": "MessagePack-CSharp", "product": "MessagePack-CSharp", "versions": [{"status": "affected", "version": "< 2.5.303"}, {"status": "affected", "version": ">= 3.0.0, < 3.1.9"}]}]}], "published": "2026-10-15T19:17:48.703", "references": [{"url": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/commit/7fd78bbf3476e03beae8b0f7a521125525a8a64a", "source": "security-advisories@github.com"}, {"url": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/commit/95b63fca4f7097d3cac12d1a95286af4b4bbf02c", "source": "security-advisories@github.com"}, {"url": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/releases/tag/v2.5.303", "source": "security-advisories@github.com"}, {"url": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/releases/tag/v3.1.9", "source": "security-advisories@github.com"}, {"url": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-qhrr-8q5h-9q3h", "source": "security-advisories@github.com"}], "vulnStatus": "Awaiting Analysis", "weaknesses": [{"type": "Secondary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-1325"}]}], "descriptions": [{"lang": "en", "value": "MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.303 and 3.1.9, deserializing attacker-controlled MessagePack data as System.Object through PrimitiveObjectFormatter can cause excessive memory allocation. The formatter allocates an object[] from each declared array length before the configured object-graph depth limit rejects the input, while nested array headers can reuse the same trailing unread bytes to satisfy per-header length validation. A comparatively small payload can therefore keep many large arrays alive at once. When an attacker can submit such data repeatedly, the allocations can cause severe managed-heap pressure, excessive garbage collection, process termination, or loss of service. Exposure requires an application to deserialize untrusted data through the affected formatter path and permit repeated attacker-controlled submissions, such as a reachable ASP.NET Core SignalR hub method with an object parameter and AddMessagePackProtocol() enabled. This issue is fixed in versions 2.5.303 and 3.1.9."}], "lastModified": "2026-10-16T16:00:33.533", "sourceIdentifier": "security-advisories@github.com"}