CVE-2026-30871Network attack vector

Unauthenticated code execution via unbounded PTR-name copy

Published Mar 19, 2026 · Updated Mar 19, 2026

Stack buffer overflow in OpenWrt before 24.10.6 and 25.12.0-rc1 through 25.12.0 allows remote attackers to execute code via mDNS. The parse_question function passes an expanded PTR name from the 8,096-byte name_buffer to unbounded strcpy operations targeting 256-byte stack buffers. The umdns package must be installed and listening on the attacker’s multicast domain; no authentication or user interaction is required.

CVSS severity9.5
Critical
EPSS probability1.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack buffer overflow in OpenWrt before 24.10.6 and 25.12.0-rc1 through 25.12.0 allows remote attackers to execute code via mDNS. The parse_question function passes an expanded PTR name from the 8,096-byte name_buffer to unbounded strcpy operations targeting 256-byte stack buffers. The umdns package must be installed and listening on the attacker’s multicast domain; no authentication or user interaction is required.

The record

CVE
CVE-2026-30871
Published
Mar 19, 2026
Updated
Mar 19, 2026
Vendor
OpenWrt
Product
OpenWrt
Classifications
CWE-121, T1210
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 19, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 24.10.6
  2. Affected versionversion=>= 25.12.0-rc1, < 25.12.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

OpenWrt · OpenWrtversion=< 24.10.6; version=>= 25.12.0-rc1, < 25.12.1

Published CVSS scores

9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.5GitHubCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-121Stack-based Buffer Overflow
T1210Exploitation of Remote Services

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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