VulnerabilityPublished 10 Nov 2025Updated 18 Nov 2025

CVE-2025-63835: Tenda AC18 · Stack-based Buffer Overflow

Source CVE Database V5

Not known to be exploited · CVSS 6.5 Medium.

Data as of 26 Oct 2026, 16:39 UTC

CVSS 3.1 base score

6.5Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.6% chance of exploitation in 30 days – higher than 52% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector: Adjacent
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Adjacent: The vulnerable component is bound to the network stack, but the attack is limited at the protocol level to a logically adjacent topology. This can mean an attack must be launched from the same shared physical (e.g., Bluetooth or IEEE 802.11) or logical (e.g., local IP subnet) network, or from within a secure or otherwise limited administrative domain (e.g., MPLS, secure VPN to an administrative network zone).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 10 Nov 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

AI-suggested

Immediately segment networks to isolate Tenda AC18 routers from critical systems and sensitive data to limit attack surface.
Disable the guest Wi-Fi feature if it is not in use, as the vulnerability resides in the guestSsid parameter.
Implement strict access controls on the local network to prevent unauthorized devices from connecting and attempting exploitation.
Monitor router logs and network traffic for unusual requests to the /goform/WifiGuestSet interface or signs of device instability and crashes.
Where possible, replace vulnerable Tenda AC18 routers with alternative devices from vendors with timely security updates.
Apply network-level protections such as intrusion detection/prevention systems (IDS/IPS) to detect and block attempts to exploit this vulnerability.
Stay alert for official patches or firmware updates from Tenda and apply them promptly once available.
Educate users about the risks of connecting unknown devices to the network and enforce strong network access policies.

Description

A stack-based buffer overflow vulnerability was discovered in Tenda AC18 v15.03.05.05_multi. The vulnerability exists in the guestSsid parameter of the /goform/WifiGuestSet interface. Remote attackers can exploit this vulnerability by sending oversized data to the guestSsid parameter, leading to denial of service (device crash) or potential remote code execution.

Impact

For European organizations, the primary impact of CVE-2025-63835 is the potential for denial of service attacks against Tenda AC18 routers, which could disrupt internet connectivity and internal network access. This is particularly critical for small and medium enterprises (SMEs) and home office setups that rely on these routers for network access and may lack redundant infrastructure. While the vulnerability does not directly compromise confidentiality or integrity, a successful remote code execution exploit could allow attackers to gain control over the router, leading to network reconnaissance, traffic interception, or pivoting attacks within the network. Disruption of network availability could impact business operations, remote work capabilities, and access to cloud services. The lack of authentication requirement lowers the barrier for exploitation, increasing risk in environments where network segmentation is weak. The absence of patches means organizations must rely on interim mitigations, increasing operational risk until a fix is available.

CWE-121Stack-based Buffer Overflow (opens in a new tab)
Variant weaknessLikelihood of exploit: HighCWE Top 25 (2025): #14
A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).
Operation · Build and Compilation · Environment Hardening
Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index…
Architecture and Design
Use an abstraction library to abstract away risky APIs. Not a complete solution.
Implementation
Implement and perform bounds checking on input.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

github.com/babraink/cve_report/blob/main/cve_report/tenda/tendaAC18/2_wifiguest_guestssid_overflow/README.md (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Description

AI analysisMachine-generated, updated 18 Nov 2025, 17:28 UTC

WeaknessesCWE-121

Technical details

References

Community reviews

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