CVE-2026-30871
Stack-Based Buffer Overflow in OpenWrt mdns Daemon (PTR Queries
Publication date: 2026-03-19
Last updated on: 2026-03-24
Assigner: GitHub, Inc.
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| openwrt | openwrt | to 24.10.6 (exc) |
| openwrt | openwrt | From 25.12.0 (inc) to 25.12.1 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-121 | A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function). |
Attack-Flow Graph
AI Powered Q&A
What immediate steps should I take to mitigate this vulnerability?
The vulnerability has been fixed in OpenWrt versions 24.10.6 and 25.12.1. Immediate mitigation involves upgrading the mdns daemon to at least these versions.
Can you explain this vulnerability to me?
This vulnerability is a stack-based buffer overflow in the mdns daemon of the OpenWrt Project's Linux operating system for embedded devices. It occurs in the parse_question function when handling PTR queries for reverse DNS domains (.in-addr.arpa and .ip6.arpa). Specifically, DNS packets received on UDP port 5353 are expanded into a large 8096-byte global buffer, which is then copied without bounds into a smaller 256-byte stack buffer using strcpy. The overflow happens because non-printable ASCII bytes are converted into multi-character octal representations, inflating the size beyond the stack buffer's capacity. A specially crafted DNS packet can exploit this to overflow the stack buffer during normal multicast DNS processing.
How can this vulnerability impact me? :
This vulnerability can lead to a stack-based buffer overflow, which may allow an attacker to execute arbitrary code or cause a denial of service on affected devices running vulnerable versions of OpenWrt. Since the issue is reachable through normal multicast DNS packet processing, an attacker could exploit it remotely by sending crafted DNS packets to the device.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
I don't know
How can this vulnerability be detected on my network or system? Can you suggest some commands?
I don't know