CVE-2020-5234 json
Untrusted data can lead to DoS attack in MessagePack for C# and Unity
published 2020-01-31 6 y ago modified 2026-09-10 1 mo ago also GHSA-7q36-4xx7-xcxf , EUVD-2020-0254
- cvss
- 4.8
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.6%
- EPSS 1.6% chance of exploitation in 30 days, percentile 75%
- public exploits
- 0
- none known
Summary
MessagePack for C# and Unity before version 1.9.11 and 2.1.90 has a vulnerability where untrusted data can lead to DoS attack due to hash collisions and stack overflow. Review the linked GitHub Security Advisory for more information and remediation steps.
Patch / fix
- nuget MessagePack 1.9.11, 2.1.90
- nuget MessagePack.ImmutableCollection 1.9.11, 2.1.90
- nuget MessagePack.ReactiveProperty 1.9.11, 2.1.90
- nuget MessagePack.UnityShims 1.9.11, 2.1.90
- nuget MessagePack.Unity 1.9.11, 2.1.90
- messagepack messagepack 1.9.3, 2.1.80
Exploit prediction
1.58% chance of exploitation in the next 30 days, higher than 75% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 4.8 | CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:N/A:H |
| NVD | 3.1 | 6.5 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
| NVD | 2.0 | 6.8 | AV:N/AC:L/Au:S/C:N/I:N/A:C |
| GitHub | 3.1 | 4.8 | CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:N/A:H |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| nuget | MessagePack | <1.9.11 >=2.0.0, <2.1.90 |
1.9.11 2.1.90 |
| nuget | MessagePack.ImmutableCollection | <1.9.11 >=2.0.0, <2.1.90 |
1.9.11 2.1.90 |
| nuget | MessagePack.ReactiveProperty | <1.9.11 >=2.0.0, <2.1.90 |
1.9.11 2.1.90 |
| nuget | MessagePack.UnityShims | <1.9.11 >=2.0.0, <2.1.90 |
1.9.11 2.1.90 |
| nuget | MessagePack.Unity | <1.9.11 >=2.0.0, <2.1.90 |
1.9.11 2.1.90 |
Affected products
- neuecc MessagePack
- neuecc MessagePack.ImmutableCollection
- neuecc MessagePack.ReactiveProperty
- neuecc MessagePack.UnityShims
Classification
References
-
github.com
/neuecc/MessagePack-CSharp/commit/56fa86219d01d0a183babbbbcb34abbdea588a02
web, patch, third-party-advisory
-
github.com
/neuecc/MessagePack-CSharp/commit/f88684078698386df02204f13faeff098a61f007
web
-
github.com
/neuecc/MessagePack-CSharp/security/advisories/GHSA-7q36-4xx7-xcxf
web, third-party-advisory
-
github.com
/neuecc/MessagePack-CSharp/issues/810
web
-
github.com
/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-7q36-4xx7-xcxf
web
-
nvd.nist.gov
/vuln/detail/CVE-2020-5234
advisory
-
github.com
/aspnet/Announcements/issues/405
web
-
github.com
/MessagePack-CSharp/MessagePack-CSharp
package
Sources
- CVE List CVE-2020-5234
- GitHub Advisory GHSA-7q36-4xx7-xcxf
- NVD CVE-2020-5234
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.