CVE-2026-48109

Source
https://cve.org/CVERecord?id=CVE-2026-48109
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-48109.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-48109
Aliases
Downstream
Related
Published
2026-06-22T21:19:54.234Z
Modified
2026-08-12T03:51:20.003654978Z
Severity
  • 8.2 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H CVSS Calculator
Summary
MessagePack-CSharp: LZ4 decompression may fail with AccessViolationException after dereferencing memory from bad input
Details

MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.301 and 3.1.7, A vulnerability exists in the optional LZ4 decompression path used by MessagePack compression modes Lz4Block and Lz4BlockArray. The decoder implementation is based on a deprecated fast-decompression algorithm that does not take a source-length bound. A remote attacker can send a crafted MessagePack payload with manipulated LZ4 token/length fields to force out-of-bounds reads from the compressed input buffer. In affected environments, this can trigger an AccessViolationException during decompression, causing process termination (denial of service). Under some conditions, limited unintended memory disclosure from over-read data may also be possible before failure. This vulnerability is fixed in 2.5.301 and 3.1.7.

Database specific
{
    "cwe_ids": [
        "CWE-20"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48109.json",
    "cna_assigner": "GitHub_M"
}
References

Affected packages

Git / github.com/messagepack-csharp/messagepack-csharp

Affected ranges

Type
GIT
Repo
https://github.com/messagepack-csharp/messagepack-csharp
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
Introduced
Fixed
Database specific
Show details
{
    "cpe": "cpe:2.3:a:messagepack:messagepack:*:*:*:*:*:c\\#:*:*",
    "extracted_events": [
        {
            "introduced": "0"
        },
        {
            "fixed": "2.5.301"
        },
        {
            "introduced": "3.0.3"
        },
        {
            "fixed": "3.1.7"
        }
    ],
    "source": "CPE_RANGE"
}

Affected versions

0.*
0.1.0-beta
0.2.0-beta
1.*
1.0.1
v1.*
v1.0.2
v1.0.3
v1.1.1
v1.1.2
v1.2.0
v1.2.1
v1.2.3
v1.3.0
v1.3.1
v1.3.2
v1.3.3
v1.4.0
v1.4.1
v1.4.2
v1.4.4
v1.5.0
v1.5.1
v1.6.0
v1.6.1
v1.6.1.2
v1.6.2
v1.7.0
v1.7.2
v1.7.3
v1.7.3.1
v1.7.3.2
v1.7.3.3
v1.7.3.4
v2.*
v2.0.110-alpha
v2.0.119-beta
v2.0.123-beta
v2.0.204-beta
v2.0.270-rc
v2.0.94-alpha
v2.1.115
v2.1.143
v2.1.152
v2.1.165
v2.1.194
v2.1.80
v2.1.90
v2.2.113
v2.2.60
v2.2.85
v2.3.75
v2.3.85
v2.4.23-alpha
v2.4.35
v2.4.59
v2.5.103
v2.5.108
v2.5.124
v2.5.129
v2.5.140
v2.5.168
v2.5.171
v2.5.172
v2.5.187
v2.5.192
v2.5.198
v2.5.94
v3.*
v3.0.3
v3.0.300
v3.0.301
v3.1.0
v3.1.1
v3.1.2
v3.1.3
v3.1.4
v3.1.5
v3.1.6

Database specific

source
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-48109.json"