CVE-2026-30872
CRITICALCVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Lifecycle Timeline
2Description
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.
Analysis
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. …
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Remediation
Within 24 hours: Identify all affected systems running versions and apply vendor patches immediately. If patching is delayed, consider network segmentation to limit exposure.
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