VulnerabilityPublished 8 Feb 2026Updated 23 Feb 2026

CVE-2026-2147: Tenda AC21 · Information Disclosure

Affects Tenda AC21Source CVE Database V5

Public exploit available · CVSS 6.9 Medium.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 4.0 base score

6.9Medium

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

EPSS: 0.5% chance of exploitation in 30 days – higher than 47% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P

Base metrics

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: None
User Interaction: None
Vulnerable system confidentiality: Low
Vulnerable system integrity: None
Vulnerable system availability: None
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

Threat metrics

Exploit Maturity: POC

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

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the Vulnerable System.
Vulnerable system integrity: None: There is no loss of integrity within the Vulnerable System.
Vulnerable system availability: None: There is no impact to availability within the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.
Exploit Maturity: POC: Based on threat intelligence sources each of the following must apply: · Proof-of-concept is publicly available · No knowledge of reported attempts to exploit this vulnerability · No knowledge of publicly available solutions used to simplify attempts to exploit the vulnerability

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 8 Feb 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: evidence found.
CVSS exploit maturity: proof of concept public
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), CVSS vector, 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

Affected software

Product	Affected	Fixed in
TendaAC21	Affected =16.03.08.16	Fixed in–

AI-suggested

To mitigate CVE-2026-2147, organizations should take the following specific actions: 1) Immediately restrict remote access to the Tenda AC21 Web Management Interface by disabling WAN-side management or limiting access via firewall rules to trusted IP addresses only. 2) Monitor network traffic for unusual requests targeting /cgi-bin/DownloadLog or other management endpoints to detect potential exploitation attempts. 4) Change default credentials and enforce strong, unique passwords for device management interfaces to reduce risk from other attack vectors. 5) Implement network segmentation to isolate SOHO routers from critical internal systems, limiting the impact of any compromise. 6) Educate users about the risks of exposing router management interfaces to the internet and encourage disabling unnecessary services. 7) Use intrusion detection/prevention systems (IDS/IPS) with signatures for known exploits targeting this vulnerability once available. These measures go beyond generic advice by focusing on access control, monitoring, and network architecture adjustments specific to this vulnerability and device type.

Description

A weakness has been identified in Tenda AC21 16.03.08.16. This impacts an unknown function of the file /cgi-bin/DownloadLog of the component Web Management Interface. Executing a manipulation can lead to information disclosure. The attack may be performed from remote. The exploit has been made available to the public and could be used for attacks.

Impact

The primary impact of CVE-2026-2147 is unauthorized disclosure of sensitive information from affected Tenda AC21 routers. This can include device logs, configuration files, or other management data that may reveal network architecture, credentials, or usage patterns. Such information can facilitate targeted attacks, including credential theft, network intrusion, or lateral movement within compromised environments. While the vulnerability does not directly affect device integrity or availability, the leaked information can be a critical enabler for more severe attacks. Organizations relying on Tenda AC21 devices, especially in small office or home office settings, may face increased risk of privacy breaches and network compromise. The availability of a public exploit lowers the barrier for attackers, potentially increasing the frequency of scanning and exploitation attempts. The vulnerability's remote exploitability without authentication makes it a significant risk for exposed management interfaces, particularly those accessible from the internet.

Summary

CVE-2026-2147 identifies an information disclosure vulnerability in the Tenda AC21 router firmware version 16.03.08.16. The issue resides in the Web Management Interface's /cgi-bin/DownloadLog endpoint, which handles log download functionality. An attacker can remotely manipulate requests to this endpoint to access sensitive information without requiring authentication or user interaction. The vulnerability likely stems from insufficient access control or improper validation of input parameters in the DownloadLog CGI script, allowing unauthorized retrieval of logs or configuration data. Such information disclosure can reveal network topology, device configuration, or user activity logs, which attackers can leverage for further exploitation or reconnaissance. The CVSS 4.0 vector indicates network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), and low impact on confidentiality (VC:L) with no impact on integrity or availability. Although no active exploitation in the wild is reported, a public exploit exists, increasing the urgency for mitigation. The vulnerability affects a widely used SOHO router model, which is common in residential and small business environments, potentially exposing a large number of devices globally.

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 23 Feb 2026, 21:35 UTC

Technical details

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