GHSA-hv8m-jj95-wg3x

Suggest an improvement
Source
https://github.com/advisories/GHSA-hv8m-jj95-wg3x
Import Source
https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-hv8m-jj95-wg3x/GHSA-hv8m-jj95-wg3x.json
JSON Data
https://api.osv.dev/v1/vulns/GHSA-hv8m-jj95-wg3x
Aliases
  • CVE-2026-48109
Downstream
Published
2026-06-11T20:34:10Z
Modified
2026-06-11T20:45:59.326687633Z
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's LZ4 decompression may fail with AccessViolationException after dereferencing memory from bad input
Details

Impact

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 issue affects applications that deserialize untrusted data while LZ4 compression is enabled.

Patches

The v2 versions are patched as of 2.5.301. The v3 versions are patched as of 3.1.7.

Workarounds

Instead of upgrading, an application may take the following precautions:

  1. Disable LZ4 compression for untrusted input paths (Lz4Block, Lz4BlockArray).
  2. Only accept compressed payloads from strongly trusted producers.
  3. Isolate deserialization in a separate process/container with restart supervision to limit availability impact.

Resources

  • MESSAGEPACKCSHARP-010
Database specific 
{
    "severity": "HIGH",
    "nvd_published_at": null,
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-11T20:34:10Z",
    "cwe_ids": []
}
References

Affected packages

NuGet / MessagePack

Package

Name
MessagePack
View open source insights on deps.dev
Purl
pkg:nuget/MessagePack

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
2.5.301

Affected versions

0.*
0.1.0-beta
0.2.0-beta
0.2.1-beta
0.2.2-beta
0.2.3-beta
0.3.0-beta
0.4.0
0.4.1
0.4.2
0.5.0
0.6.0
0.6.1
0.7.0
0.7.2
0.8.0
0.8.1
0.8.2
0.8.3
0.8.4
0.8.5
1.*
1.0.0
1.0.1
1.0.2
1.0.3
1.1.0
1.1.1
1.1.1.1
1.1.2
1.2.0
1.2.0.1
1.2.0.2
1.2.1
1.2.2
1.2.3
1.3.0
1.3.1
1.3.1.1
1.3.2
1.3.3
1.4.0
1.4.1
1.4.2
1.4.3
1.4.4
1.5.0
1.5.0.1
1.5.0.2
1.5.1
1.6.0
1.6.0.1
1.6.0.2
1.6.0.3
1.6.1
1.6.1.1
1.6.1.2
1.6.2
1.7.0
1.7.1
1.7.2
1.7.3
1.7.3.1
1.7.3.2
1.7.3.3
1.7.3.4
1.7.3.7
1.8.71-beta
1.8.74
1.8.80
1.9.3-g129239b107
1.9.3
1.9.11
2.*
2.0.107-alpha
2.0.108-alpha
2.0.110-alpha
2.0.110-alpha-g1e44a9106f
2.0.119-beta
2.0.123-beta
2.0.171-beta
2.0.204-beta
2.0.221-beta
2.0.231-rc
2.0.270-rc
2.0.299-rc
2.0.323
2.0.335
2.1.80
2.1.90
2.1.115
2.1.143
2.1.152
2.1.165
2.1.194
2.2.36-alpha
2.2.44-rc
2.2.60
2.2.85
2.2.113
2.3.58-alpha
2.3.73-alpha
2.3.75
2.3.85
2.3.112
2.4.14-alpha
2.4.23-alpha
2.4.35
2.4.59
2.5.64-alpha
2.5.94
2.5.103
2.5.108
2.5.124
2.5.129
2.5.140
2.5.168
2.5.171
2.5.172
2.5.187
2.5.192
2.5.198
2.5.205

Database specific

source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-hv8m-jj95-wg3x/GHSA-hv8m-jj95-wg3x.json"

NuGet / MessagePack

Package

Name
MessagePack
View open source insights on deps.dev
Purl
pkg:nuget/MessagePack

Affected ranges

Type
ECOSYSTEM
Events
Introduced
3.0.214-rc.1
Fixed
3.1.7

Affected versions

3.*
3.0.300
3.0.308
3.1.0
3.1.1
3.1.2
3.1.3
3.1.4
3.1.5
3.1.6

Database specific

source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-hv8m-jj95-wg3x/GHSA-hv8m-jj95-wg3x.json"