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UK Cyber Defence
VulnerabilityAnalyzed

CVE-2026-34121

An authentication bypass vulnerability within the HTTP handling of the DS configuration service in TP-Link Tapo C520WS v2.6 was identified, due to inconsistent parsing and authorization logic in JSON requests during authentication check.

HIGH 8.7EPSS 0.45%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.45%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

An authentication bypass vulnerability within the HTTP handling of the DS configuration service in TP-Link Tapo C520WS v2.6 was identified, due to inconsistent parsing and authorization logic in JSON requests during authentication check. An unauthenticated attacker can append an authentication-exempt action to a request containing privileged DS do actions, bypassing authorization checks. Successful exploitation allows unauthenticated execution of restricted configuration actions, which may result in unauthorized modification of device state.

CVSS 4.0
8.7 HIGHCVSS: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/M
EPSS
0.45% probability · 38th percentile
CISA KEV
Not listed
Weakness
CWE-287
Affected
tp-link/tapo c520ws firmware
Source
f23511db-6c3e-4e32-a477-6aa17d310630

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.