CVE-2026-48502
MessagePack-CSharp: Denial of service vulnerabilities can swamp the CPU or crash the process with stack and heap overflows
- Published
- Updated
- Reserved
- Assigned by
- GitHub_M
Description
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.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 4.0 | High8.2 | 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 |
| NVDNVD · Analyzed | 4.0 | High8.2 | 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
- EPSS (exploitation in 30 days)
- 0.44% · top 62% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.2.
Weakness
- CWE-125: Out-of-bounds Read (opens in a new tab)All about CWE-125 and its CVEs
- CWE-190: Integer Overflow or Wraparound (opens in a new tab)All about CWE-190 and its CVEs
- CWE-407: Inefficient Algorithmic Complexity (opens in a new tab)All about CWE-407 and its CVEs
- CWE-409: Improper Handling of Highly Compressed Data (Data Amplification) (opens in a new tab)All about CWE-409 and its CVEs
- CWE-470: Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection') (opens in a new tab)All about CWE-470 and its CVEs
- CWE-502: Deserialization of Untrusted Data (opens in a new tab)All about CWE-502 and its CVEs
- CWE-674: Uncontrolled Recursion (opens in a new tab)All about CWE-674 and its CVEs
- CWE-789: Memory Allocation with Excessive Size Value (opens in a new tab)All about CWE-789 and its CVEs
- CWE-1188: Insecure Default Initialization of Resource (opens in a new tab)All about CWE-1188 and its CVEs
Affected products
MessagePack-CSharp · MessagePack-CSharp
- affected >= 3.1.7, < 3.1.7
- affected < 2.5.301
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- NuGetMessagePackGHSA-382j-8mxh-c7x2 (opens in a new tab)
References (1)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-382j-8mxh-c7x2 (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-48502)Record last updated .