CVE Intelligence
Medium Memory corruption

CVE-2026-6241 — Authenticated Format String Vulnerability in ONVIF AddScopes Method on TP-Link Tapo C520WS

An authenticated format string vulnerability is present in the ONVIF AddScopes in Tapo C520WS v2, where user-controlled input is improperly passed to formatting functions without adequate sanitization. An attacker can inject format specifiers into ONVIF scope parameters to manipulate memory handling behavior. Successful exploitation may cause the ONVIF management service to crash, resulting in DoS condition that impacts normal device operation.

Published Jun 5, 2026 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: TPLink

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 0.3% (30-day exploitation probability)+2
  • Technical severity (medium)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
0.26%
ahead of 16% of scored CVEs · Oct 14, 2026
Affects
TP-Link Systems Inc.
Tapo C520WS v2
CVSS base
6.8
Medium · 2 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
None
none · proof-of-concept · active
Automatable
No
can an attacker script the kill-chain steps
Technical impact
Partial
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (TP-Link Systems Inc. Tapo C520WS v2).
  2. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  3. Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
TP-Link Systems Inc. Tapo C520WS v2 < 1.2.6 Build 260528 Vulnerable CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Adjacent
Attack complexity
Low
Attack requirements
None
Privileges required
High
User interaction
None
Scope
X
Confidentiality (vulnerable system)
None
Integrity (vulnerable system)
None
Availability (vulnerable system)
High
Confidentiality (subsequent)
None
Integrity (subsequent)
None
Availability (subsequent)
None

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
6.8 CVSS 4.0 Medium — — f23511db-6c3e-4e32-a477-6aa17d310630 via NIST National Vulnerability Database
6.8 CVSS 4.0 Medium — — TPLink via CVE Program (cve.org) e CISA ADP
CVSS:4.0/AV:A/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/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 (score shown at the top: f23511db-6c3e-4e32-a477-6aa17d310630)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-134 · Use of Externally-Controlled Format String

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.26%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.
endpoint telemetry (EDR)crash dumps

Timeline

What happened to this CVE, newest first.

  • 2026
  • Affected products added · tp-link systems inc./tapo c520ws v2
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • SSVC assessment updated
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 13, 2026
  • CVSS changed · 6.8
    Oct 13, 2026 · NIST National Vulnerability Database
  • Source status changed · → Deferred
    Oct 13, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 13, 2026 · NIST National Vulnerability Database
  • CVE published
    Jun 5, 2026 · TPLink

Source activity

Repeated readings are counted rather than listed.

  • 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

3 on the record

Elsewhere on this site

TP-Link Systems Inc.
every CVE for this vendor
Memory corruption
same class
CWE-134
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-6242 Authenticated Format String Vulnerability in ONVIF Subscribe Service on TP-Link Tapo C520WS Jun 5, 2026
  • CVE-2026-6240 Authenticated Stack-based Buffer Overflow in ONVIF DeleteUsers Service on TP-Link Tapo C520WS Jun 5, 2026
  • CVE-2026-6239 Authenticated Stack-based Buffer Overflow in ONVIF CreateUsers Service in TP-Link Tao C520WS Jun 5, 2026
  • CVE-2026-34123 Whitelist Validation Bypass in TP-Link Tapo C520WS Jun 5, 2026
  • CVE-2026-8714 Denial-of-Service Vulnerability in RTSP Input Handling on TP-Link's Tapo C520WS Jun 5, 2026
  • CVE-2026-0919 Unauthenticated Denial of Service via Oversized URL in HTTP Parser on TP-Link Tapo C210, C220 & C520WS Jan 27, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No fixed version, patch or mitigation documented.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-6241 is "Authenticated Format String Vulnerability in ONVIF AddScopes Method on TP-Link Tapo C520WS", rated Medium. It affects Tapo C520WS v2 (TP-Link Systems Inc.); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 6.8 describes technical severity. EPSS 0.26% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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