PT-2021-17345 · NetGear · Netgear R6400+1

Published 2021-02-24 · Updated 2021-04-02 · CVE-2021-27239

Positive Technologies (AI Summary)

CVSS v3.1

8.8

High

Base vector

AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Name of the Vulnerable Software and Affected Versions: NETGEAR R6400 and R6700 firmware version 1.0.4.98

Description: This issue allows network-adjacent attackers to execute arbitrary code on affected installations of NETGEAR routers. Authentication is not required to exploit this issue. The specific flaw exists within the upnpd service, which listens on UDP port 1900 by default. A crafted MX header field in an SSDP message can trigger an overflow of a fixed-length stack-based buffer. An attacker can leverage this issue to execute code in the context of root.

Recommendations: For NETGEAR R6400 and R6700 firmware version 1.0.4.98, as a temporary workaround, consider disabling the upnpd service until a patch is available. Restrict access to UDP port 1900 to minimize the risk of exploitation. Avoid using crafted MX header fields in SSDP messages until the issue is resolved. At the moment, there is no information about a newer version that contains a fix for this issue.

Fix

Stack Overflow

Weakness Enumeration

CWE-121

Related Identifiers

CVE-2021-27239

ZDI-21-206

Affected Products

Netgear R6400

Netgear R6700

References · 5

• https://zerodayinitiative.com/advisories/ZDI-21-206 · Security Note
• https://nvd.nist.gov/vuln/detail/CVE-2021-27239 · Security Note
• https://kb.netgear.com/000062820/Security-Advisory-for-Stack-based-Buffer-Overflow-Remote-Code-Execution-Vulnerability-on-Some-Routers-PSV-2020-0432 · Vendor Advisory
• https://osv.dev/vulnerability/CVE-2021-27239 · Vendor Advisory
• https://t.me/cvenotify/12510 · Telegram Post