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Vulnerability · Published Mar 19, 2026 · Assigned by GitHub_M

CVE-2026-30872OpenWrt Project has a Stack-based Buffer Overflow vulnerability via IPv6 reverse DNS lookup

Critical 9.5

In plain English

A critical-severity stack buffer overflow in openwrt from openwrt. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 2.4% (higher than 84% of all known vulnerabilities).

Severity (CVSS 4.0)9.5Critical
Exploit odds (30 days)2.4%top 16.2% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

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.

Affected products (as reported)

VendorProductVersions
openwrt openwrt >= 25.12.0-rc1, < 25.12.1< 24.10.6

Weakness: CWE-121 · Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

References