Detections
Analytics
EulerOS 2.0 SP12 : unbound (EulerOS-SA-2026-2574)
critical Nessus Plugin ID 326203
Synopsis
The remote EulerOS host is missing multiple security updates.Description
According to the versions of the unbound packages installed, the EulerOS installation on the remote host is affected by the following vulnerabilities :NLnet Labs Unbound up to and including version 1.25.0 is vulnerable to poisoning via promiscuous records for the authority section. Promiscuous RRSets that complement DNS replies in the authority section can be used to trick Unbound to cache such records. If an adversary is able to attach such records in a reply (i.e., spoofed packet, fragmentation attack) he would be able to poison Unbound's cache. A malicious actor can exploit the possible poisonous effect by injecting RRSets other than NS that are also accompanied by address records in a reply, for example MX. This could be achieved by trying to spoof a reply packet or fragmentation attacks. Unbound would then accept the relative address records in the additional section and cache them if the authority RRSet has enough trust at this point, i.e., in-zone data for the delegation point. Unbound 1.25.1 contains a patch with a fix that disregards address records from the additional section if they are not explicitly relevant only to authority NS records, mitigating the possible poison effect. This is a complement fix to CVE-2025-11411.(CVE-2026-42960)
NLnet Labs Unbound 1.16.2 up to and including version 1.25.0 has a vulnerability of the 'ghost domain names' family of attacks that could extend the ghost domain window by up to one cached TTL configured value. Similar to other 'ghost domain names' attacks, an adversary needs to control a (ghost) zone and be able to query a vulnerable Unbound. A single client NS query can cause Unbound to overwrite the cached expired parent-side referral NS rrset with the child-side apex NS rrset and essentially extend the ghost domain window by up to one cached TTL configured value ('cache-max-ttl'). In configurations where 'harden- referral-path: yes' is used (non-default configuration), no client NS query is required since Unbound implicitly performs that query. Unbound 1.25.1 contains a patch with a fix that does not allow extension of TTLs for (parent) NS records regardless of their trust.(CVE-2026-40622)
NLnet Labs Unbound up to and including version 1.25.0 is vulnerable to a degradation of service attack related to parsing long lists of incoming EDNS options. An adversary sending queries with too many EDNS options can hold Unbound threads hostage while they are parsing and creating internal data structures for the options. Coordinated attacks can result in degradation and/or denial of service. Unbound 1.25.1 contains a patch with a fix to limit acceptable incoming EDNS options (100).(CVE-2026-41292)
NLnet Labs Unbound up to and including version 1.25.0 has a denial of service vulnerability in the DNSSEC validator that can lead to a crash given malicious upstream replies. When Unbound constructs chase-reply messages for validation, the code uses the wrong counter to calculate write offsets for ADDITIONAL section rrsets. DNAME duplication could increase the ANSWER section count and authority filtering could decrease the AUTHORITY section count and create an uninitialized array slot. Combining these two, the validator later dereferences this uninitialized pointer, causing an immediate process crash. An adversary controlling a DNSSEC-signed domain can trigger this bug with a single query by configuring a DNAME chain with unsigned CNAMEs and a response containing unsigned AUTHORITY records alongside signed ADDITIONAL glue records. Unbound 1.25.1 contains a patch with a fix to use the proper counters to calculate the write offsets.(CVE-2026-42959)
NLnet Labs Unbound 1.19.1 up to and including version 1.25.0 has a vulnerability in the DNSSEC validator that enables denial of service and possible remote code execution as a result of deep copying a data structure and erroneously overwriting a destination pointer. An adversary can exploit the vulnerability by controlling a malicious signed zone and querying a vulnerable Unbound. When DS sub-queries need to suspend validation due to NSEC3 computational budget exhaustion (introduced in Unbound 1.19.1), Unbound deep- copies response messages to preserve them across memory region teardown. A struct-assignment bug overwrites the destination's pointer with the source's pointer. After the sub-query region is freed, the resumed validator dereferences this dangling pointer, triggering a crash or potentially enabling arbitrary code execution. Unbound 1.25.1 contains a patch with a fix to preserve the correct pointer when deep copying the data structure.(CVE-2026-33278)
Tenable has extracted the preceding description block directly from the EulerOS unbound 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 affected unbound packages.See Also
Plugin Details
Severity: Critical
ID: 326203
File Name: EulerOS_SA-2026-2574.nasl
Version: 1.1
Type: Local
Family: Huawei Local Security Checks
Published: 7/10/2026
Updated: 7/10/2026
Supported Sensors: Nessus
Risk Information
VPR
Risk Factor: Medium
Score: 6.9
Percentile: 96.92
CVSS v2
Risk Factor: Critical
Base Score: 10
Temporal Score: 7.4
Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C
CVSS Score Source: CVE-2026-33278
CVSS v3
Risk Factor: Critical
Base Score: 10
Temporal Score: 8.7
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:H
Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C
CVSS Score Source: CVE-2026-42960
CVSS v4
Risk Factor: Critical
Base Score: 10
Threat Score: 9.1
Threat Vector: CVSS:4.0/E:U
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
Vulnerability Information
CPE: p-cpe:/a:huawei:euleros:unbound-help, p-cpe:/a:huawei:euleros:unbound, p-cpe:/a:huawei:euleros:python3-unbound, p-cpe:/a:huawei:euleros:unbound-libs, cpe:/o:huawei:euleros:2.0
Required KB Items: Host/local_checks_enabled, Host/cpu, Host/EulerOS/release, Host/EulerOS/rpm-list, Host/EulerOS/sp
Excluded KB Items: Host/EulerOS/uvp_version
Exploit Ease: No known exploits are available
Patch Publication Date: 7/10/2026
Vulnerability Publication Date: 5/20/2026
Reference Information
CVE: CVE-2026-33278, CVE-2026-40622, CVE-2026-41292, CVE-2026-42959, CVE-2026-42960