EUVD-2026-13247
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Lifecycle Timeline
3Description
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 parse_question function. The issue is triggered by PTR queries for reverse DNS domains (.in-addr.arpa and .ip6.arpa). DNS packets received on UDP port 5353 are expanded by dn_expand into an 8096-byte global buffer (name_buffer), which is then copied via an unbounded strcpy into a fixed 256-byte stack buffer when handling TYPE_PTR queries. The overflow is possible because dn_expand converts non-printable ASCII bytes (e.g., 0x01) into multi-character octal representations (e.g., \001), significantly inflating the expanded name beyond the stack buffer's capacity. A crafted DNS packet can exploit this expansion behavior to overflow the stack buffer, making the vulnerability reachable through normal multicast DNS packet processing. This issue has been fixed in versions 24.10.6 and 25.12.1.
Analysis
Remote code execution in OpenWrt mdns daemon (versions before 24.10.6 and 25.12.1) allows unauthenticated attackers to crash the service or execute arbitrary code by sending specially crafted DNS PTR queries to UDP port 5353, exploiting a stack buffer overflow in the parse_question function. The vulnerability occurs when domain names are expanded and copied without bounds checking, with non-printable characters inflating the payload beyond the fixed 256-byte buffer. …
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Remediation
Within 24 hours: Identify all OpenWrt-based devices in your infrastructure and document their versions; establish emergency change control for critical patches. Within 7 days: Deploy patches to versions 24.10.6 or 25.12.1 on all accessible OpenWrt systems; prioritize network-critical devices (routers, gateways). …
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