CVE-2023-43135Network attack vector

Unauthenticated backend access via exposed user tokens

Published Sep 20, 2023 · Updated Sep 25, 2024

Missing authorization in TP-Link TL-ER5120G 4.0 firmware 2.0.0 Build 210817 allows remote attackers to obtain backend access tokens. The public record does not identify the affected request handler or explain how it returns sensitive device data and user tokens without an authentication check. Network access to the web management service is sufficient to obtain a token and log in to backend management without prior credentials.

CVSS severity9.8
Critical
EPSS probability0.77%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Missing authorization in TP-Link TL-ER5120G 4.0 firmware 2.0.0 Build 210817 allows remote attackers to obtain backend access tokens. The public record does not identify the affected request handler or explain how it returns sensitive device data and user tokens without an authentication check. Network access to the web management service is sufficient to obtain a token and log in to backend management without prior credentials.

The record

CVE
CVE-2023-43135
Published
Sep 20, 2023
Updated
Sep 25, 2024
Vendor
TP-Link
Product
TL-ER5120G
Classifications
CWE-862, T1528
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 20, 2023CVE publishedPublication date reported by the CVE source.
  2. Sep 25, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=4.0_2.0.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

TP-Link · TL-ER5120Gversion=4.0_2.0.0

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A: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-862Missing Authorization
T1528Steal Application Access Token

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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo