SB2026060825 - Red Hat Enterprise Linux 8 update for unbound
Published: June 8, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 2 vulnerabilities.
1) Heap-based buffer overflow (CVE-ID: CVE-2026-42944)
CWE-ID: CWE-122 - Heap-based Buffer Overflow
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to a heap-based buffer overflow in the EDNS option encoder when processing queries containing multiple NSID and/or DNS Cookie EDNS and/or EDNS Padding options. A remote attacker can send a specially crafted query to cause a denial of service.
Only instances with the relevant EDNS options enabled are vulnerable.
2) Access of Uninitialized Pointer (CVE-ID: CVE-2026-42959)
CWE-ID: CWE-824 - Access of Uninitialized Pointer
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to use of an uninitialized pointer in the DNSSEC validator when constructing chase-reply messages for validation. A remote attacker can provide a malicious upstream reply to cause a denial of service.
Exploitation requires control of a DNSSEC-signed domain and can be triggered with a single query using a DNAME chain with unsigned CNAMEs and a response containing unsigned AUTHORITY records alongside signed ADDITIONAL glue records.
Remediation
Install update from vendor's website.