CVE-2026-48516

MEDIUM EPSS 13.9%
Published Jun 22, 20261w ago · Modified Jun 23, 20261w ago
6.3 CVSS 4.0
Medium
Find Similar
Published Jun 22, 2026 1w ago
Last Modified Jun 23, 2026 1w ago

Description

MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.301 and 3.1.7, InterfaceLookupFormatter<TKey,TElement> constructs an internal Dictionary<TKey, IGrouping<TKey,TElement>> with the default equality comparer instead of the security-aware comparer supplied by options.Security.GetEqualityComparer<TKey>(). This formatter omission allows hash-collision CPU denial of service against ILookup<TKey,TElement> even when the application has opted into the untrusted-data security posture This vulnerability is fixed in 2.5.301 and 3.1.7.

CVSS Details

Base Score
6.3
Exploitability
—
Impact
—
Vector string
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/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
Attack Vector Network
Attack Complexity High
Privileges Required None
User Interaction None
Scope X

Threat Intelligence

EPSS Exploit Probability
13.9% percentile
Exploit & Patch Status
No Known Exploit
No Patch Available

Weaknesses 1

CWE-407

Affected Products 2

VendorProductVersionRange
messagepackmessagepack* <2.5.301
messagepackmessagepack*≥3.0.3  –  <3.1.7

References 1

  • github.com https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-q2h6-ghwm-5qm8
    Vendor AdvisoryMitigation

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.