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CVE-2026-30871 Detail

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.


Metrics

NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

Nist CVSS score does not match with CNA score
CNA:  GitHub, Inc.
CVSS-B 9.5 CRITICAL
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 to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://github.com/openwrt/openwrt/releases/tag/v24.10.6 GitHub, Inc.
https://github.com/openwrt/openwrt/releases/tag/v25.12.1 GitHub, Inc.
https://github.com/openwrt/openwrt/security/advisories/GHSA-7c3j-f7w2-p8f6 GitHub, Inc.

Weakness Enumeration

CWE-ID CWE Name Source
CWE-121 Stack-based Buffer Overflow GitHub, Inc.  

Change History

1 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-30871
NVD Published Date:
03/19/2026
NVD Last Modified:
03/19/2026
Source:
GitHub, Inc.