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CVE-2026-30872

CRITICAL CVSS 4.0: 9.5 EPSS 0.09%
Updated Mar 24, 2026
Openwrt
Parameter Value
CVSS 9.5 (CRITICAL)
Affected Versions 25.12.0 — 25.12.1
Fixed In 24.10.6
Type CWE-121 (Stack-based Buffer Overflow)
Vendor Openwrt
Public PoC No

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.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
High
Difficult to exploit
Attack Requirements
None
No additional conditions
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed

Impact Assessment

Confidentiality
High
Complete data leak
Integrity
High
Complete data modification
Availability
High
Complete denial of service

CVSS Vector v4.0

Vulnerable Products 2

Configuration From (including) Up to (excluding)
Openwrt Openwrt
cpe:2.3:o:openwrt:openwrt:*:*:*:*:*:*:*:*
24.10.6
Openwrt Openwrt
cpe:2.3:o:openwrt:openwrt:*:*:*:*:*:*:*:*
25.12.0 25.12.1