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CVE-2026-30871— OpenWrt Project has Stack-based Buffer Overflow in DNS PTR Query

Quick assessment

Affected
openwrt openwrt
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

OpenWrt是OpenWrt开源的一套针对嵌入式设备的Linux操作系统。 OpenWrt 24.10.6之前版本和25.12.1之前版本存在安全漏洞，该漏洞源于mdns守护进程的parse_question函数存在栈缓冲区溢出，可能导致远程代码执行。

AI Predicted 8.8 Difficulty: Easy EPSS 0.67% · P50

Possible ATT&CK Techniques 1 AI

T1203 · Exploitation for Client Execution
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I. Basic Information for CVE-2026-30871

Vulnerability Information
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Vulnerability Title
OpenWrt Project has Stack-based Buffer Overflow in DNS PTR Query
Source: CVE Program / CVE List V5
Vulnerability 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 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.
Source: CVE Program / CVE List V5
CVSS Information
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
Source: CVE Program / CVE List V5
Vulnerability Type
栈缓冲区溢出
Source: CVE Program / CVE List V5
Vulnerability Title
OpenWrt 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
OpenWrt是OpenWrt开源的一套针对嵌入式设备的Linux操作系统。 OpenWrt 24.10.6之前版本和25.12.1之前版本存在安全漏洞，该漏洞源于mdns守护进程的parse_question函数存在栈缓冲区溢出，可能导致远程代码执行。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
openwrt openwrt < 24.10.6 -

II. Public POCs for CVE-2026-30871

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III. Intelligence Information for CVE-2026-30871

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Vendor Advisories for CVE-2026-30871 (1)

Vendor Pages for CVE-2026-30871 (2)

Same Patch Batch · openwrt · 2026-03-19 · 5 CVEs total

CVE-2026-32721 8.6 HIGH LuCI luci-mod-network: Possible XSS attack in WiFi scan on Joining Wireless Client modal
CVE-2026-30873 OpenWrt Project jsonpath: Memory leak when processing strings, labels, and regexp tokens
CVE-2026-30872 OpenWrt Project has a Stack-based Buffer Overflow vulnerability via IPv6 reverse DNS looku
CVE-2026-30874 OpenWrt procd PATH Environment Variable Filter Bypass via Incorrect String Comparison Lead

IV. Related Vulnerabilities

Same product: openwrt
Same vendor: openwrt
Same weakness: CWE-121

V. Comments for CVE-2026-30871

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