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CVE-2026-33594— Outgoing DoH excessive memory allocation

Quick assessment

Affected
PowerDNS DNSdist
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 DNSdist是PowerDNS公司的一个提供DNS流量负载均衡与安全防护能力的代理软件。 PowerDNS DNSdist存在安全漏洞，该漏洞源于客户端可通过生成大量路由到过载DoH后端的查询触发过度内存分配，导致查询累积到缓冲区中，直到连接结束才释放。

CVSS 5.3 · Medium EPSS 0.80% · P55
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I. Basic Information for CVE-2026-33594

Vulnerability Information
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Vulnerability Title
Outgoing DoH excessive memory allocation
Source: CVE Program / CVE List V5
Vulnerability Description
A client can trigger excessive memory allocation by generating a lot of queries that are routed to an overloaded DoH backend, causing queries to accumulate into a buffer that will not be released until the end of the connection.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
PowerDNS DNSdist 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
PowerDNS DNSdist是PowerDNS公司的一个提供DNS流量负载均衡与安全防护能力的代理软件。 PowerDNS DNSdist存在安全漏洞，该漏洞源于客户端可通过生成大量路由到过载DoH后端的查询触发过度内存分配，导致查询累积到缓冲区中，直到连接结束才释放。
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 DNSdist 1.9.0 ~ 1.9.13 -

II. Public POCs for CVE-2026-33594

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III. Intelligence Information for CVE-2026-33594

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Vendor Advisories for CVE-2026-33594 (1)

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-2026-33261 5.9 MEDIUM Null pointer accces in aggressive NSEC(3) cache
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-2026-33256 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: DNSdist
Same vendor: PowerDNS

V. Comments for CVE-2026-33594

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