SB2026100176 - openEuler 24.03 LTS SP1 update for unbound

Description

This security bulletin contains information about 3 vulnerabilities.

1) Resource exhaustion (CVE-ID: CVE-2026-80225)

CWE-ID: CWE-400 - Resource exhaustion

CVSSv4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to uncontrolled resource consumption in Unbound's TCP/DoT reading procedure when processing a sustained stream of distinct uncached names over a TCP/DoT connection. A remote attacker can stream distinct uncached names at a sustained rate to cause a denial of service.

2) Heap-based buffer overflow (CVE-ID: CVE-2026-81634)

CWE-ID: CWE-122 - Heap-based Buffer Overflow

CVSSv4: 0 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:N/SA:N]

The vulnerability allows a remote attacker to cause memory corruption.

The vulnerability exists due to improper buffer length validation in the RRSet canonicalisation routine when processing a 255-length query name with a large TCP response. A remote attacker can provide a crafted DNS response to cause memory corruption.

Canonicalisation occurs before DNSSEC validation.

3) Heap-based buffer overflow (CVE-ID: CVE-2026-82717)

CWE-ID: CWE-122 - Heap-based Buffer Overflow

CVSSv4: 9.2 [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]

The vulnerability allows a remote attacker to execute arbitrary code.

The vulnerability exists due to a heap-based buffer overflow in the CNAME synthesis packet-buffer handling logic when processing a crafted upstream DNS response that requires max TTL rewriting. A remote attacker can send a specially crafted upstream DNS response to execute arbitrary code.

Successful code execution depends on the system configuration, compilation options, and heap memory layout.

Remediation

Install update from vendor's website.

References

• https://www.openeuler.org/en/security/security-bulletins/detail/?id=openEuler-SA-2026-4148