Zld
CVE-2020-25014
CRITICAL
Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Lifecycle Timeline
1DescriptionNVD
A stack-based buffer overflow in fbwifi_continue.cgi on Zyxel UTM and VPN series of gateways running firmware version V4.30 through to V4.55 allows remote unauthenticated attackers to execute arbitrary code via a crafted http packet.
AnalysisAI
A stack-based buffer overflow in fbwifi_continue.cgi on Zyxel UTM and VPN series of gateways running firmware version V4.30 through to V4.55 allows remote unauthenticated attackers to execute. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Technical ContextAI
This vulnerability is classified as Out-of-bounds Write (CWE-787), which allows attackers to write data beyond allocated buffer boundaries leading to code execution or crashes. A stack-based buffer overflow in fbwifi_continue.cgi on Zyxel UTM and VPN series of gateways running firmware version V4.30 through to V4.55 allows remote unauthenticated attackers to execute arbitrary code via a crafted http packet. Affected products include: Zyxel Zld, Zyxel Access Points Firmware.
RemediationAI
No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Validate write boundaries, use memory-safe languages, enable compiler protections (ASLR, stack canaries).
A directory traversal vulnerability in the web management interface of Zyxel ATP series firmware versions V5.00 through
A command injection vulnerability in the IPSec VPN feature of Zyxel ATP series firmware versions from V4.32 through V5.3
A null pointer dereference vulnerability in Zyxel ATP series firmware versions from V4.32 through V5.38, USG FLEX series
An integer overflow vulnerability in the source code of the QuickSec IPSec toolkit used in the VPN feature of the Zyxel
A post-authentication command injection vulnerability in Zyxel ATP series firmware versions from V4.60 through V5.38 and
A post-authentication command injection vulnerability in Zyxel ATP series firmware versions from V4.32 through V5.38, US
A post-authentication command injection vulnerability in Zyxel ATP series firmware versions from V5.00 through V5.38, US
Certain Zyxel products allow command injection by an admin via an input string to chg_exp_pwd during a password-change a
A reflected cross-site scripting (XSS) vulnerability in the CGI program "dynamic_script.cgi" of Zyxel ATP series firmwar
A cross-site scripting (XSS) vulnerability in the CGI program of the Zyxel ATP series firmware versions 5.10 through 5.3
An improper privilege management vulnerability in the hotspot feature of the Zyxel USG FLEX series firmware versions 4.5
An improper privilege management vulnerability in the debug CLI command of the Zyxel ATP series firmware versions 4.32 t
Same weakness CWE-787 – Out-of-bounds Write
View allSame technique Buffer Overflow
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External POC / Exploit Code
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