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RHEL 9 : brotli (RHSA-2026:90890)

critical Nessus Plugin ID 373557

Synopsis

The remote Red Hat host is missing a security update.

Description

The remote Redhat Enterprise Linux 9 host has packages installed that are affected by a vulnerability as referenced in the RHSA-2026:90890 advisory.

 Brotli is a generic-purpose lossless compression algorithm that compresses data using a combination of a modern variant of the LZ77 algorithm, Huffman coding and 2nd order context modeling, with a compression ratio comparable to the best currently available general-purpose compression methods. It is similar in speed with deflate but offers more dense compression.

 Security Fix(es):

 * brotli: Out-of-Bounds Write in Google Brotli Decoder (CVE-2026-111497)

 Bug Fix(es) and Enhancement(s):

 * Incorrect Python parameter name in brotli makes CVE-2025-66471 fixes ineffective (JIRA:RHEL-221128)

 For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Update the affected packages.

See Also

https://access.redhat.com/errata/RHSA-2026:90890

https://access.redhat.com/security/updates/classification/#important

https://bugzilla.redhat.com/show_bug.cgi?id=2558973

http://www.nessus.org/u?cadf6af6

Plugin Details

Severity: Critical

ID: 373557

File Name: redhat-RHSA-2026-90890.nasl

Version: 1.1

Type: Local

Agent: unix

Published: 10/29/2026

Updated: 10/29/2026

Supported Sensors: Nessus Agent, Continuous Assessment, Nessus

Risk Information

VPR

Risk Factor: Critical

Score: 9.4

Percentile: 99.83

Vendor

Vendor Severity: Important

CVSS v2

Risk Factor: Critical

Base Score: 10

Temporal Score: 8.7

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

CVSS Score Source: CVE-2026-111497

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 9.4

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

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

CVSS v4

Risk Factor: Critical

Base Score: 9.2

Threat Score: 9.2

Threat Vector: CVSS:4.0/E:A

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

Vulnerability Information

CPE: cpe:/o:redhat:rhel_eus:9.6, p-cpe:/a:redhat:enterprise_linux:brotli-devel, p-cpe:/a:redhat:enterprise_linux:brotli, p-cpe:/a:redhat:enterprise_linux:libbrotli, p-cpe:/a:redhat:enterprise_linux:python3-brotli

Required KB Items: Host/local_checks_enabled, Host/RedHat/release, Host/RedHat/rpm-list, Host/cpu

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 10/27/2026

Vulnerability Publication Date: 10/21/2026

CISA Known Exploited Vulnerability Due Dates: 11/10/2026

Reference Information

CVE: CVE-2026-111497

CWE: 787

RHSA: 2026:90890