Detections
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Echo: expat: security update to 2.8.4-2

high Tenable Cloud Security Plugin ID 464343

Description

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

 - Expat before 2.8.5 fails to validate that a high surrogate in UTF-16 input is followed by a low surrogate,
 allowing malformed UTF-16 sequences to be accepted. Attackers can supply UTF-16 encoded XML containing
 lone high surrogates that consume the following code unit, causing Expat to pass unpaired surrogates to
 applications built with XML_UNICODE and to silently replace input characters in other builds.
 (CVE-2026-93990)

Solution

Update the expat library and its related packages to version 2.8.4-2 or later.

See Also

https://advisory.echohq.com/cve/CVE-2026-93990

Plugin Details

Severity: High

ID: 464343

Version: Revision 1.2

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: Medium

Score: 5.8

Percentile: 96.1

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 5.8

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

CVSS Score Source: CVE-2026-93990

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:H/A:N

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

CVSS v4

Risk Factor: High

Base Score: 8.7

Threat Score: 6.6

Threat Vector: CVSS:4.0/E:U

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

Vulnerability Information

Exploit Ease: No known exploits are available

Patch Publication Date: 9/20/2026

Vulnerability Publication Date: 9/19/2026

Reference Information

CVE: CVE-2026-93990

IAVA: 2026-A-1045