---
cve: "CVE-2026-48502"
severity: "HIGH"
cvss: 8.2
epss: "26%"
vendor: "MessagePack-CSharp"
kev: false
exploited: false
published: "2026-06-22 22:16:47"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-07T07:26:14+02:00"
---

# CVE-2026-48502

> 8.2 HIGH · 🧪 PoC

## Beschreibung

MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.301 and 3.1.7, MessagePackReader.ReadDateTime() can allocate stack memory based on an attacker-controlled MessagePack extension length. In the slow path for timestamp extension parsing, the computed tokenSize includes the extension body length from the wire and is used in a stackalloc operation before the extension length is validated as one of the valid timestamp sizes. A very small payload can claim a large timestamp extension body and cause a stack allocation large enough to trigger an uncatchable StackOverflowException, terminating the host process. This vulnerability is fixed in 2.5.301 and 3.1.7.

## CVSS-Vektor

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

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Hoch | good |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |

## Patch verfügbar (OSV)

- 5657b1e34ea2869a2ca6bc0aa6617158620201ba (Commit)
- 1b53ae8b7681340199faf337bcbb0eb5aed702de (Commit)

## Referenzen

- <https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-382j-8mxh-c7x2>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-48502) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_