Openwrt
CVE-2026-30872
CRITICAL
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessSend crafted PTR query for IPv6 reverse DNS
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DeliverymDNS daemon receives multicast on UDP 5353
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Exploitstrcpy copies unvalidated domain name
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ExecutionStack buffer overflow in match_ipv6_addresses
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ImpactExecute arbitrary code with daemon privileges
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A06:2021 - Vulnerable and Outdated Components
ASVS 5.0
V14 - Configuration Dependency management, component inventory
MITRE ATT&CK
1 technique across 1 tactic: Execution The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Exploitation Conditions | OpenWrt versions prior to 24.10.6 and 25.12.1 with mdns daemon enabled. Remote unauthenticated attacker sends crafted PTR queries for IPv6 reverse DNS domains (.ip6.arpa) via multicast DNS on UDP port 5353. No victim interaction required. |
| Impact | Successful exploitation can lead to arbitrary code execution, denial of service, or privilege escalation depending on the memory layout and protections in place. |
| Exploit ScenarioDerived | An attacker sends an oversized input to a vulnerable function, overwriting the return address on the stack to redirect execution to attacker-controlled shellcode. |
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Alert meAnalysisAIv1 – Mar 19, 2026
Remote code execution in OpenWrt's mDNS daemon (versions before 24.10.6 and 25.12.1) allows unauthenticated attackers to overflow a 46-byte stack buffer by sending malformed IPv6 PTR queries over multicast DNS on UDP port 5353. The vulnerability stems from insufficient validation of domain name length before copying to a fixed-size buffer, enabling arbitrary code execution on affected embedded devices. No patch is currently available.
Earlier versions of this analysis (1)
RemediationAI
Use memory-safe languages or bounds-checked functions. Enable ASLR, DEP/NX, and stack canaries. Apply vendor patches promptly.
Affects your stack
Find out whether the stacks and servers you run are on an affected version.
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
A buffer overflow occurs when data written to a buffer exceeds its allocated size, potentially overwriting adjacent memory and corrupting program state. This vulnerability is classified as Stack-based Buffer Overflow (CWE-121).
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Primary rating from GitHub Advisory · only source for this CVE.
CVSS VectorGitHub Advisory
DescriptionGitHub Advisory
OpenWrt Project is a Linux operating system targeting embedded devices. In versions prior to 24.10.6 and 25.12.1, the mdns daemon has a Stack-based Buffer Overflow vulnerability in the match_ipv6_addresses function, triggered when processing PTR queries for IPv6 reverse DNS domains (.ip6.arpa) received via multicast DNS on UDP port 5353. During processing, the domain name from name_buffer is copied via strcpy into a fixed 256-byte stack buffer, and then the reverse IPv6 request is extracted into a buffer of only 46 bytes (INET6_ADDRSTRLEN). Because the length of the data is never validated before this extraction, an attacker can supply input larger than 46 bytes, causing an out-of-bounds write. This allows a specially crafted DNS query to overflow the stack buffer in match_ipv6_addresses, potentially enabling remote code execution. This issue has been fixed in versions 24.10.6 and 25.12.1.
Executive ViewAI
Organizations using versions face critical risk from CVE-2026-30872, a stack-based buffer overflow vulnerability rated CVSS 9.8. Exploitation could allow attackers to corrupt memory, crash the application, or potentially execute arbitrary code. Organizations should apply vendor updates immediately when available and implement compensating controls in the interim.
Apply vendor patch. If immediate patching is not feasible: (1) Enable ASLR and DEP where available; (2) Implement network segmentation; (3) Monitor for exploitation indicators.
Threat Intelligence Overview
NVD
CVE.org
EPSS
GitHub
VulDB
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.
A stack-based buffer overflow occurs when a program writes more data to a buffer located on the stack than it was allocated to hold.
Remote Code Execution represents the critical moment when an attacker successfully runs arbitrary code on a target system without physical access.
Affected Products (CPE)GitHub Advisory
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Exploit-DB