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CVE-2026-50248— BOGUS configured primary hostname accepted for XFR in auth/rpz zones

CVSS 6.5 · Medium EPSS 0.13% · P3

Possible ATT&CK Techniques 1AI

T1498 · Network Denial of Service

Affected Version Matrix 1

VendorProductVersion RangeStatus
NLnet LabsUnbound1.7.0< 1.25.2affected
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I. Basic Information for CVE-2026-50248

Vulnerability Information
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Vulnerability Title
BOGUS configured primary hostname accepted for XFR in auth/rpz zones
Source: CVE Program / CVE List V5
Vulnerability Description
In NLnet Labs Unbound 1.7.0 up to and including 1.25.1, when an auth/rpz zone has a configured primary hostname that resolves to BOGUS A/AAAA, it is still considered as a possible XFR endpoint. A malicious actor that can spoof the hostname's A/AAAA record (no valid RRSIG required) becomes the zone's XFR primary and can replaces the entire zone/the resolver's entire response policy.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:L
Source: CVE Program / CVE List V5
Vulnerability Type
对数据真实性的验证不充分
Source: CVE Program / CVE List V5
Vulnerability Title
NLnet Labs Unbound 输入验证错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
NLnet Labs Unbound是荷兰NLnet Labs组织的域名系统解析服务器。 NLnet Labs Unbound 1.7.0至1.25.1版本存在输入验证错误漏洞，该漏洞源于当auth/rpz区域配置的主机名解析为BOGUS A/AAAA时仍被视为可能的XFR端点，导致恶意攻击者可通过伪造主机名的A/AAAA记录成为区域的XFR主节点并替换整个区域或解析器的响应策略。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

VendorProductAffected VersionsCPESubscribe
NLnet LabsUnbound 1.7.0 ~ 1.25.2 -

II. Public POCs for CVE-2026-50248

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III. Intelligence Information for CVE-2026-50248

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Vendor Advisories for CVE-2026-50248 (1)

Same Patch Batch · NLnet Labs · 2026-07-22 · 24 CVEs total

CVE-2026-559737.5 HIGH'dns-error-reporting: yes' leads to stack buffer overflow
CVE-2026-326657.5 HIGHRemote DNS-over-QUIC denial of service due to `quic-size` budget bypass
CVE-2026-406917.5 HIGHPacket of death for DNSCrypt over TCP
CVE-2026-446907.5 HIGHCross-zone wildcard cache poisoning via RRSIG.labels manipulation
CVE-2026-528635.9 MEDIUMMemory corruption could lead to crash and denial of service
CVE-2026-557175.9 MEDIUM'serve-expired-client-timeout' and 'response-ip' CNAME redirect could lead to a crash
CVE-2026-559915.9 MEDIUMRemote DNS-over-QUIC (DoQ) flow-control assertion failure in libngtcp2
CVE-2026-500465.9 MEDIUMPossible heap use-after-free in an error path when a DoT forwarded query is jostled out
CVE-2026-559905.9 MEDIUMPacket of death for a DNSCrypt misconfigured Unbound
CVE-2026-564445.9 MEDIUMDegradation of resolution service when 'discard-timeout' and 'serve-expired-client-timeout
CVE-2026-446215.9 MEDIUMLibunbound applications configured with 'unwanted-reply-threshold' could eventually be abr
CVE-2026-145865.9 MEDIUMAssertion in libngtcp2 when under pressure in high concurrency DNS-over-QUIC environments
CVE-2026-502515.3 MEDIUMAttacker supplied '0.0.0.0'/'::' glue triggers defensive full-cache flush
CVE-2026-500455.3 MEDIUM'max-global-quota' reset by DNSSEC validation restarts
CVE-2026-564164.8 MEDIUMPossible heap buffer overflow when validator canonicalizes RDATA that contains domain name
CVE-2026-465823.7 LOWA wildcard replay, as another piece of data, triggers poisoning in the serve expired reply
CVE-2026-446873.7 LOWOff-by-one error in 'harden-below-nxdomain' logic can shadow a stub/forward zone by a legi
CVE-2026-416373.7 LOWDegradation of resolution service from improperly accounted client-terminated DNS-over-QUI
CVE-2026-544783.7 LOWDNS Cookie bypass when combined with proxy-protocol use
CVE-2026-429553.7 LOWExtra fix for CVE-2026-40622 to also clamp the TTL of A/AAAA records disallowing a one-tim

Showing top 20 of 24 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Unbound
Same vendor: NLnet Labs
Same weakness: CWE-345

V. Comments for CVE-2026-50248

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