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CVE-2026-33261— Null pointer accces in aggressive NSEC(3) cache

Quick assessment

Affected
PowerDNS Recursor
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

PowerDNS Recursor（pdns_recursor）是荷兰PowerDNS公司的一款域名解析服务器。 PowerDNS Recursor存在安全漏洞，该漏洞源于从NSEC到NSEC3的区域转换可能触发内部不一致，导致拒绝服务。

CVSS 5.9 · Medium EPSS 0.23% · P12

Possible ATT&CK Techniques 1 AI

T1499.002 · Service Exhaustion Flood
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I. Basic Information for CVE-2026-33261

Vulnerability Information
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Vulnerability Title
Null pointer accces in aggressive NSEC(3) cache
Source: CVE Program / CVE List V5
Vulnerability Description
A zone transition from NSEC to NSEC3 might trigger an internal inconsistency and cause a denial of service.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
PowerDNS Recursor 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
PowerDNS Recursor（pdns_recursor）是荷兰PowerDNS公司的一款域名解析服务器。 PowerDNS Recursor存在安全漏洞，该漏洞源于从NSEC到NSEC3的区域转换可能触发内部不一致，导致拒绝服务。
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

Vendor Product Affected Versions CPE Subscribe
PowerDNS Recursor 5.4.0 ~ 5.4.1 -

II. Public POCs for CVE-2026-33261

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III. Intelligence Information for CVE-2026-33261

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Same Patch Batch · PowerDNS · 2026-04-22 · 22 CVEs total

CVE-2026-33593 7.5 HIGH Denial of service via crafted DNSCrypt query
CVE-2026-33608 7.4 HIGH Incomplete domain name sanitization during
CVE-2026-33602 6.5 MEDIUM Off-by-one access when processing crafted UDP responses
CVE-2026-33611 6.5 MEDIUM Insufficient validation of HTTPS and SVCB records
CVE-2026-33262 5.9 MEDIUM Insufficient validation of cookie reply
CVE-2026-33610 5.9 MEDIUM Possible file descriptor exhaustion in forward-dnsupdate
CVE-2026-33260 5.3 MEDIUM Insufficient input validation of internal webserver
CVE-2026-33609 5.3 MEDIUM LDAP DN injection
CVE-2026-33254 5.3 MEDIUM Resource exhaustion via DoQ/DoH3 connections
CVE-2026-33595 5.3 MEDIUM DoQ/DoH3 excessive memory allocation
CVE-2026-33594 5.3 MEDIUM Outgoing DoH excessive memory allocation
CVE-2026-33256 5.3 MEDIUM Unbounded memory allocation by internal web server
CVE-2026-33257 5.3 MEDIUM Insufficient input validation of internal webserver
CVE-2026-33258 5.3 MEDIUM Crafted zones can cause increased resource usage
CVE-2026-33259 5.0 MEDIUM Concurrent modification of RPZ data can lead to denial of servce
CVE-2026-33598 4.8 MEDIUM Out-of-bounds read in cache inspection via Lua
CVE-2026-33601 4.4 MEDIUM Insufficient validation of zonemd record
CVE-2026-33600 4.4 MEDIUM Null pointer dereference in RPZ transfer
CVE-2026-33597 3.7 LOW PRSD detection denial of service
CVE-2026-33596 3.1 LOW TCP backend stream ID overflow

Showing top 20 of 22 CVEs. View all on vendor page → →

IV. Related Vulnerabilities

Same product: Recursor
Same vendor: PowerDNS

V. Comments for CVE-2026-33261

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