CyberSecBulletin
CVE-2026-108473NVD status: Deferred

HS103 v5: Missing Authentication for Critical Functionality

Published Updated By the CyberSecBulletin desk

CVE-2026-108473 is a high-severity missing authentication for critical functionality vulnerability in HS103 v5 from TP-Link, with a CVSS 4.0 base score of 8.7 out of 10. It can be exploited from the same local network by an unauthenticated attacker, without any action from a user. The record lists version 1.1.3 Build 250908 Rel.112508 as the first without the flaw, so updating HS103 v5 to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.27% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update HS103 v5 to 1.1.3 Build 250908 Rel.112508 or a later version.
  2. Update EP10 v1 to 1.1.1 Build 250908 Rel.112508 or a later version.
  3. Update EP40 v1 to 1.1.0 Build 250225 Rel.171723 or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
TP-LinkHS103 v5before 1.1.3 Build 250908 Rel.1125081.1.3 Build 250908 Rel.112508
TP-LinkEP10 v1before 1.1.1 Build 250908 Rel.1125081.1.1 Build 250908 Rel.112508
TP-LinkEP40 v1before 1.1.0 Build 250225 Rel.1717231.1.0 Build 250225 Rel.171723
TP-LinkHS200 v5before 1.1.2 Build 241220 Rel.1655591.1.2 Build 241220 Rel.165559
TP-LinkKP401 v1before 1.1.2 Build 241223 Rel.0944341.1.2 Build 241223 Rel.094434
TP-LinkKS230 KIT v2before 1.1.4 Build 241223 Rel.1058301.1.4 Build 241223 Rel.105830
TP-LinkKP405 v1before 1.1.0 Build 250225 Rel.1746321.1.0 Build 250225 Rel.174632
TP-LinkHS220 v3before 1.1.4 Build 241220 Rel.1710501.1.4 Build 241220 Rel.171050
TP-LinkKP115 v1before 1.1.1 Build 250908 Rel.1129451.1.1 Build 250908 Rel.112945
TP-LinkHS210 v3before 1.1.0 Build 250225 Rel.1634251.1.0 Build 250225 Rel.163425
TP-LinkHS300 v2before 1.1.2 Build 241220 Rel.1713331.1.2 Build 241220 Rel.171333
TP-LinkKP200 v3before 1.1.0 Build 250225 Rel.1717241.1.0 Build 250225 Rel.171724
TP-LinkKP303 v2before 1.1.2 Build 241220 Rel.1733211.1.2 Build 241220 Rel.173321
TP-LinkKS200 v1before 1.1.2 Build 241223 Rel.1038571.1.2 Build 241223 Rel.103857
TP-LinkEP40A v1before 1.1.1 Build 250908 Rel.1125261.1.1 Build 250908 Rel.112526
TP-LinkKS220 v1before 1.1.3 Build 241223 Rel.1055151.1.3 Build 241223 Rel.105515
TP-LinkKS200M v1before 1.1.4 Build 241223 Rel.1047001.1.4 Build 241223 Rel.104700
TP-LinkES20M v1before 1.1.6 Build 250522 Rel.2102541.1.6 Build 250522 Rel.210254
TP-LinkKS220M v1before 1.1.6 Build 250522 Rel.2102541.1.6 Build 250522 Rel.210254
TP-LinkKP400 v3before 1.1.0 Build 250225 Rel.1717231.1.0 Build 250225 Rel.171723
TP-LinkKL125 v4before 1.1.1 Build 260710 Rel.0826461.1.1 Build 260710 Rel.082646
TP-LinkKL135 v2before 1.1.1 Build 260710 Rel.0826461.1.1 Build 260710 Rel.082646
TP-LinkKL110 v4before 1.1.1 Build 260710 Rel.0826461.1.1 Build 260710 Rel.082646
TP-LinkKL420L5 v1before 1.4.2 Build 260605 Rel.0350331.4.2 Build 260605 Rel.035033

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
AdjacentThe attacker must be on the same local network segment.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Attack requirements
NoneThe attack does not depend on a particular deployment or configuration.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Confidentiality (vulnerable system)
HighSerious loss of confidentiality on the vulnerable system.
Integrity (vulnerable system)
HighSerious loss of integrity on the vulnerable system.
Availability (vulnerable system)
HighSerious loss of availability on the vulnerable system.
Confidentiality (other systems)
NoneNo loss of confidentiality on systems beyond the vulnerable one.
Integrity (other systems)
NoneNo loss of integrity on systems beyond the vulnerable one.
Availability (other systems)
NoneNo loss of availability on systems beyond the vulnerable one.

Vector: CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. Scored by CNA.

Official description

Multiple Kasa devices contain an improper authentication vulnerability in the local device-management protocol. An unauthenticated adjacent attacker may send management instructions to an affected device without adequate authentication or authorization, allowing modification of the device state or management settings. Under certain usage conditions involving interaction between the user, mobile application, and device-cloud service, insufficient protection of account-related communications may also expose account information. Successful exploitation may allow an unauthenticated adjacent-network attacker to perform unauthorized device-management actions and disrupt legitimate user control. Under certain conditions, account-related information may also be exposed, potentially leading to compromise of the associated cloud account.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Missing Authentication for Critical Functionality

The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.

How developers prevent this class of flaw

  • For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using libraries with authentication capabilities such as OpenSSL or the ESAPI Authenticator.
  • When storing data in the cloud (e.g., S3 buckets, Azure blobs, Google Cloud Storage, etc.), use the provider's controls to require strong authentication for users who should be allowed to access the data.

More Missing Authentication for Critical Functionality vulnerabilities (CWE-306)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Missing Authentication for Critical Functionality vulnerabilities

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