CVE-2026-12244— Heap overflow and crash with crafted SVCB RR
Possible ATT&CK Techniques 1AI
T1190 · Exploit Public-Facing ApplicationAffected Version Matrix 1
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| NLnet Labs | NSD | 4.14.0< 4.14.3 | affected |
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I. Basic Information for CVE-2026-12244
Vulnerability Information
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Vulnerability Title
Heap overflow and crash with crafted SVCB RR
Source: CVE Program / CVE List V5
Vulnerability Description
If NSD is configured as secondary for a zone, the primary of that zone can crash NSD with an AXFR containing a DNS message with a special crafted SVCB RR with an rdata size of 65512, that let's an (uint16_t) variable that is used to allocate space needed for the RR wrap (because total size > 65535), causing a heap overflow. The attacker can perform a controlled (RCE class) head write of up to 65509 bytes
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Source: CVE Program / CVE List V5
Vulnerability Type
整数溢出或超界折返
Source: CVE Program / CVE List V5
Vulnerability Title
NLnet Labs NSD 缓冲区错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
NLnet Labs NSD是荷兰NLnet Labs组织的一款DNS服务器软件。 NLnet Labs NSD 4.14.0版本至4.14.3之前版本存在安全漏洞，该漏洞源于在处理特制SVCB RR时，uint16_t变量在分配空间时发生整数溢出（总大小大于65535），导致堆溢出，攻击者可执行最多65509字节的受控头部写入。
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 |
|---|---|---|---|---|
| NLnet Labs | NSD | 4.14.0 ~ 4.14.3 | - |
II. Public POCs for CVE-2026-12244
| # | POC Description | Source Link | Shenlong Link |
|---|
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Vendor Advisories for CVE-2026-12244 (1)
- 🔗 https://www.nlnetlabs.nl/downloads/nsd/CVE-2026-12244.txtvendor-advisory
Same Patch Batch · NLnet Labs · 2026-06-25 · 4 CVEs total
| CVE-2026-12245 | Denial of DNS over TLS service by any DoT client | |
| CVE-2026-12246 | Out of bounds stack write with crafted APL RR | |
| CVE-2026-12490 | Bypass of client certificate verification with transfer over TLS |
IV. Related Vulnerabilities
Same vendor: NLnet Labs
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Remote DNS-over-QUIC (DoQ) flow-control assertion failure in - CVE-2026-55990
Packet of death for a DNSCrypt misconfigured Unbound - CVE-2026-55973
'dns-error-reporting: yes' leads to stack buffer overflow
Same weakness: CWE-190
- CVE-2026-71479
New API: Integer overflow in quota billing yields negative c - CVE-2026-73193
DBI versions before 1.652 for Perl allow a heap out-of-bound - CVE-2026-18671
IBM i is Affected By Multiple Vulnerabilities in NetServer - CVE-2026-17216
IBM i is Affected By Multiple Vulnerabilities in DRDA / DDM - CVE-2026-73645
OpenZeppelin Confidential Contracts ERC7984ERC20Wrapper: onc
V. Comments for CVE-2026-12244
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