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Echo: MessagePack: security update to 2.5.172+echo.1

medium Tenable Cloud Security Plugin ID 458924

Description

There are packages installed that are affected by a vulnerability referenced in the following CVE:

 - 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. (CVE-2026-48516)

Solution

Update the MessagePack library and its related packages to version 2.5.172+echo.1 or later.

See Also

https://advisory.echohq.com/cve/CVE-2026-48516

Plugin Details

Severity: Medium

ID: 458924

Version: Revision 1.1

Type: Local

Published: 10/2/2026

Updated: 10/5/2026

Supported Sensors: Tenable Cloud Security, Tenable Self-Hosted Container Security

Risk Information

VPR

Risk Factor: Low

Score: 3

Percentile: 23.73

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 5.8

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C

CVSS Score Source: CVE-2026-48516

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

CVSS v4

Risk Factor: Medium

Base Score: 6.3

Threat Score: 1.7

Threat Vector: CVSS:4.0/E:U

Vector: 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

Vulnerability Information

Exploit Ease: No known exploits are available

Patch Publication Date: 9/17/2026

Vulnerability Publication Date: 6/22/2026

Reference Information

CVE: CVE-2026-48516