Detections
Analytics
RHEL 9 : dnsmasq (RHSA-2026:19373)
high Nessus Plugin ID 315566
Synopsis
The remote Red Hat host is missing one or more security updates for dnsmasq.Description
The remote Redhat Enterprise Linux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:19373 advisory.The dnsmasq packages contain Dnsmasq, a lightweight DNS (Domain Name Server) forwarder and DHCP (Dynamic Host Configuration Protocol) server.
Security Fix(es):
* dnsmasq: dnsmasq: heap buffer overflow in cache via NAME_ESCAPE expansion (CVE-2026-2291)
* dnsmasq: NSEC bitmap parsing infinite loop (CVE-2026-4890)
* dnsmasq: RRSIG rdlen underflow leading to heap OOB read (CVE-2026-4891)
* dnsmasq: DHCPv6 CLID buffer overflow in helper process (CVE-2026-4892)
* dnsmasq: Broken ECS source validation bypass (CVE-2026-4893)
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 these issues but has instead relied only on the application's self-reported version number.
Solution
Update the RHEL dnsmasq package based on the guidance in RHSA-2026:19373.See Also
https://access.redhat.com/security/updates/classification/#important
https://bugzilla.redhat.com/show_bug.cgi?id=2439088
https://bugzilla.redhat.com/show_bug.cgi?id=2458516
https://bugzilla.redhat.com/show_bug.cgi?id=2458517
https://bugzilla.redhat.com/show_bug.cgi?id=2458518
https://bugzilla.redhat.com/show_bug.cgi?id=2458519
Plugin Details
Severity: High
ID: 315566
File Name: redhat-RHSA-2026-19373.nasl
Version: 1.1
Type: Local
Agent: unix
Family: Red Hat Local Security Checks
Published: 5/20/2026
Updated: 5/20/2026
Supported Sensors: Agentless Assessment, Continuous Assessment, Frictionless Assessment Agent, Frictionless Assessment AWS, Frictionless Assessment Azure, Nessus Agent, Nessus
Risk Information
VPR
Risk Factor: High
Score: 7.4
Vendor
Vendor Severity: Important
CVSS v2
Risk Factor: High
Base Score: 8.3
Temporal Score: 6.1
Vector: CVSS2#AV:A/AC:L/Au:N/C:C/I:C/A:C
CVSS Score Source: CVE-2026-4892
CVSS v3
Risk Factor: High
Base Score: 8.4
Temporal Score: 7.3
Vector: CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C
Vulnerability Information
CPE: cpe:/o:redhat:rhel_eus:9.8, p-cpe:/a:redhat:enterprise_linux:dnsmasq-utils, p-cpe:/a:redhat:enterprise_linux:dnsmasq, cpe:/o:redhat:enterprise_linux:9
Required KB Items: Host/local_checks_enabled, Host/RedHat/release, Host/RedHat/rpm-list, Host/cpu
Exploit Ease: No known exploits are available
Patch Publication Date: 5/19/2026
Vulnerability Publication Date: 5/11/2026
Reference Information
CVE: CVE-2026-2291, CVE-2026-4890, CVE-2026-4891, CVE-2026-4892, CVE-2026-4893