An update for unbound is now available for openEuler-22.03-LTS-SP4,openEuler-24.03-LTS-SP1,openEuler-24.03-LTS-SP3,openEuler-24.03-LTS-SP4,openEuler-20.03-LTS-SP4 Security Advisory openeuler-security@openeuler.org openEuler security committee openEuler-SA-2026-3232 Final 1.0 1.0 2026-08-07 Initial 2026-08-07 2026-08-07 openEuler SA Tool V1.0 2026-08-07 unbound security update An update for unbound is now available for openEuler-22.03-LTS-SP4,openEuler-24.03-LTS-SP1,openEuler-24.03-LTS-SP3,openEuler-24.03-LTS-SP4,openEuler-20.03-LTS-SP4 Unbound is a validating, recursive, caching DNS resolver. It is designed to be fast and lean and incorporates modern features based on open standards. To help increase online privacy, Unbound supports DNS-over-TLS which allows clients to encrypt their communication. Unbound is available for most platforms such as FreeBSD, OpenBSD, NetBSD, MacOS, Linux and Microsoft Windows. Unbound is a totally free, open source software under the BSD license. It doesn't make custom builds or provide specific features to paying customers only. Security Fix(es): In NLnet Labs Unbound 1.4.22 up to and including 1.25.1, UDP source port is randomized and intended to serve as a secret value that increases the entropy of DNS transactions. When resolver load balancing policies depend on the source port while their outcome is revealed this secrecy is undermined. The vulnerability arises when the load balancing policy is consistent with respect to the incoming source UDP port and IP address while heavily depending on the incoming source UDP port as a randomization source. When the SO_REUSEPORT configuration option is enabled ('so-reuseport: yes') in Unbound (by default), it meets these conditions, making it vulnerable for DNS cache poisoning attacks. Upon startup, Unbound randomly partitions the available UDP source port space into disjoint subsets of (almost) equal size, assigning each subset to a specific worker thread. When an incoming DNS query is received, the kernel’s SO_REUSEPORT load balancing mechanism deterministically assigns the query to a socket associated with a particular thread. All outgoing DNS queries generated during the resolution of that request use source ports selected exclusively from the port subset assigned to the corresponding thread. Since these port subsets are disjoint across threads, the source port observed in a resolver’s outgoing query to an authoritative name server serves as a reliable indicator of the worker thread that processed the original client query. A malicious actor can acquire the mapping between incoming UDP source ports (for a given fixed source IP address) and Unbound worker threads and leverage it to conduct DNS cache poisoning attacks by effectively lowering the random port population per thread.(CVE-2026-50252) An update for unbound is now available for openEuler-22.03-LTS-SP4,openEuler-24.03-LTS-SP1,openEuler-24.03-LTS-SP3,openEuler-24.03-LTS-SP4,openEuler-20.03-LTS-SP4. openEuler Security has rated this update as having a security impact of critical. A Common Vunlnerability Scoring System(CVSS)base score,which gives a detailed severity rating, is available for each vulnerability from the CVElink(s) in the References section. Critical unbound https://www.openeuler.org/zh/security/security-bulletins/detail/?id=openEuler-SA-2026-3232 https://www.openeuler.org/en/security/cve/detail/?cveId=CVE-2026-50252 https://nvd.nist.gov/vuln/detail/CVE-2026-50252 openEuler-22.03-LTS-SP4 openEuler-24.03-LTS-SP1 openEuler-24.03-LTS-SP3 openEuler-24.03-LTS-SP4 openEuler-20.03-LTS-SP4 unbound-1.13.2-24.oe2203sp4.src.rpm unbound-1.17.1-19.oe2403sp1.src.rpm unbound-1.17.1-18.oe2403sp3.src.rpm unbound-1.17.1-18.oe2403sp4.src.rpm unbound-1.11.0-24.oe2003sp4.src.rpm python3-unbound-1.13.2-24.oe2203sp4.aarch64.rpm unbound-1.13.2-24.oe2203sp4.aarch64.rpm unbound-anchor-1.13.2-24.oe2203sp4.aarch64.rpm unbound-debuginfo-1.13.2-24.oe2203sp4.aarch64.rpm unbound-debugsource-1.13.2-24.oe2203sp4.aarch64.rpm unbound-devel-1.13.2-24.oe2203sp4.aarch64.rpm unbound-help-1.13.2-24.oe2203sp4.aarch64.rpm unbound-libs-1.13.2-24.oe2203sp4.aarch64.rpm python3-unbound-1.17.1-19.oe2403sp1.aarch64.rpm unbound-1.17.1-19.oe2403sp1.aarch64.rpm unbound-anchor-1.17.1-19.oe2403sp1.aarch64.rpm unbound-debuginfo-1.17.1-19.oe2403sp1.aarch64.rpm unbound-debugsource-1.17.1-19.oe2403sp1.aarch64.rpm unbound-devel-1.17.1-19.oe2403sp1.aarch64.rpm unbound-help-1.17.1-19.oe2403sp1.aarch64.rpm unbound-libs-1.17.1-19.oe2403sp1.aarch64.rpm unbound-utils-1.17.1-19.oe2403sp1.aarch64.rpm python3-unbound-1.17.1-18.oe2403sp3.aarch64.rpm unbound-1.17.1-18.oe2403sp3.aarch64.rpm unbound-anchor-1.17.1-18.oe2403sp3.aarch64.rpm unbound-debuginfo-1.17.1-18.oe2403sp3.aarch64.rpm unbound-debugsource-1.17.1-18.oe2403sp3.aarch64.rpm unbound-devel-1.17.1-18.oe2403sp3.aarch64.rpm unbound-help-1.17.1-18.oe2403sp3.aarch64.rpm unbound-libs-1.17.1-18.oe2403sp3.aarch64.rpm unbound-utils-1.17.1-18.oe2403sp3.aarch64.rpm python3-unbound-1.17.1-18.oe2403sp4.aarch64.rpm unbound-1.17.1-18.oe2403sp4.aarch64.rpm unbound-anchor-1.17.1-18.oe2403sp4.aarch64.rpm unbound-debuginfo-1.17.1-18.oe2403sp4.aarch64.rpm unbound-debugsource-1.17.1-18.oe2403sp4.aarch64.rpm unbound-devel-1.17.1-18.oe2403sp4.aarch64.rpm unbound-help-1.17.1-18.oe2403sp4.aarch64.rpm unbound-libs-1.17.1-18.oe2403sp4.aarch64.rpm unbound-utils-1.17.1-18.oe2403sp4.aarch64.rpm python3-unbound-1.11.0-24.oe2003sp4.aarch64.rpm unbound-1.11.0-24.oe2003sp4.aarch64.rpm unbound-debuginfo-1.11.0-24.oe2003sp4.aarch64.rpm unbound-debugsource-1.11.0-24.oe2003sp4.aarch64.rpm unbound-devel-1.11.0-24.oe2003sp4.aarch64.rpm unbound-help-1.11.0-24.oe2003sp4.aarch64.rpm unbound-libs-1.11.0-24.oe2003sp4.aarch64.rpm python3-unbound-1.13.2-24.oe2203sp4.x86_64.rpm unbound-1.13.2-24.oe2203sp4.x86_64.rpm unbound-anchor-1.13.2-24.oe2203sp4.x86_64.rpm unbound-debuginfo-1.13.2-24.oe2203sp4.x86_64.rpm unbound-debugsource-1.13.2-24.oe2203sp4.x86_64.rpm unbound-devel-1.13.2-24.oe2203sp4.x86_64.rpm unbound-help-1.13.2-24.oe2203sp4.x86_64.rpm unbound-libs-1.13.2-24.oe2203sp4.x86_64.rpm python3-unbound-1.17.1-19.oe2403sp1.x86_64.rpm unbound-1.17.1-19.oe2403sp1.x86_64.rpm unbound-anchor-1.17.1-19.oe2403sp1.x86_64.rpm unbound-debuginfo-1.17.1-19.oe2403sp1.x86_64.rpm unbound-debugsource-1.17.1-19.oe2403sp1.x86_64.rpm unbound-devel-1.17.1-19.oe2403sp1.x86_64.rpm unbound-help-1.17.1-19.oe2403sp1.x86_64.rpm unbound-libs-1.17.1-19.oe2403sp1.x86_64.rpm unbound-utils-1.17.1-19.oe2403sp1.x86_64.rpm python3-unbound-1.17.1-18.oe2403sp3.x86_64.rpm unbound-1.17.1-18.oe2403sp3.x86_64.rpm unbound-anchor-1.17.1-18.oe2403sp3.x86_64.rpm unbound-debuginfo-1.17.1-18.oe2403sp3.x86_64.rpm unbound-debugsource-1.17.1-18.oe2403sp3.x86_64.rpm unbound-devel-1.17.1-18.oe2403sp3.x86_64.rpm unbound-help-1.17.1-18.oe2403sp3.x86_64.rpm unbound-libs-1.17.1-18.oe2403sp3.x86_64.rpm unbound-utils-1.17.1-18.oe2403sp3.x86_64.rpm python3-unbound-1.17.1-18.oe2403sp4.x86_64.rpm unbound-1.17.1-18.oe2403sp4.x86_64.rpm unbound-anchor-1.17.1-18.oe2403sp4.x86_64.rpm unbound-debuginfo-1.17.1-18.oe2403sp4.x86_64.rpm unbound-debugsource-1.17.1-18.oe2403sp4.x86_64.rpm unbound-devel-1.17.1-18.oe2403sp4.x86_64.rpm unbound-help-1.17.1-18.oe2403sp4.x86_64.rpm unbound-libs-1.17.1-18.oe2403sp4.x86_64.rpm unbound-utils-1.17.1-18.oe2403sp4.x86_64.rpm python3-unbound-1.11.0-24.oe2003sp4.x86_64.rpm unbound-1.11.0-24.oe2003sp4.x86_64.rpm unbound-debuginfo-1.11.0-24.oe2003sp4.x86_64.rpm unbound-debugsource-1.11.0-24.oe2003sp4.x86_64.rpm unbound-devel-1.11.0-24.oe2003sp4.x86_64.rpm unbound-help-1.11.0-24.oe2003sp4.x86_64.rpm unbound-libs-1.11.0-24.oe2003sp4.x86_64.rpm In NLnet Labs Unbound 1.4.22 up to and including 1.25.1, UDP source port is randomized and intended to serve as a secret value that increases the entropy of DNS transactions. When resolver load balancing policies depend on the source port while their outcome is revealed this secrecy is undermined. The vulnerability arises when the load balancing policy is consistent with respect to the incoming source UDP port and IP address while heavily depending on the incoming source UDP port as a randomization source. When the SO_REUSEPORT configuration option is enabled ('so-reuseport: yes') in Unbound (by default), it meets these conditions, making it vulnerable for DNS cache poisoning attacks. Upon startup, Unbound randomly partitions the available UDP source port space into disjoint subsets of (almost) equal size, assigning each subset to a specific worker thread. When an incoming DNS query is received, the kernel’s SO_REUSEPORT load balancing mechanism deterministically assigns the query to a socket associated with a particular thread. All outgoing DNS queries generated during the resolution of that request use source ports selected exclusively from the port subset assigned to the corresponding thread. Since these port subsets are disjoint across threads, the source port observed in a resolver’s outgoing query to an authoritative name server serves as a reliable indicator of the worker thread that processed the original client query. A malicious actor can acquire the mapping between incoming UDP source ports (for a given fixed source IP address) and Unbound worker threads and leverage it to conduct DNS cache poisoning attacks by effectively lowering the random port population per thread. 2026-08-07 CVE-2026-50252 openEuler-22.03-LTS-SP4 openEuler-24.03-LTS-SP1 openEuler-24.03-LTS-SP3 openEuler-24.03-LTS-SP4 openEuler-20.03-LTS-SP4 Critical 9.3 AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:H unbound security update 2026-08-07 https://www.openeuler.org/zh/security/security-bulletins/detail/?id=openEuler-SA-2026-3232