CVE-2026-34122 — Stack-based Buffer Overflow Leading to Denial of Service in TP-Link Tapo C520WS
A stack-based buffer overflow vulnerability was identified in TP-Link Tapo C520WS v2.6 within a configuration handling component due to insufficient input validation. An attacker can exploit this vulnerability by supplying an excessively long value for a vulnerable configuration parameter, resulting in a stack overflow. Successful exploitation results in Denial-of-Service (DoS) condition, leading to a service crash or device reboot, impacting availability.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- EPSS 0.4% (30-day exploitation probability)+4
- 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.
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.
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.
- Identify exposed assets running the affected vendor/product/version combinations (TP-Link Systems Inc. Tapo C520ws Firmware, TP-Link Systems Inc. Tapo C520WS v2.6).
- No fix documented in the sources: reduce exposure and monitor the vendor advisory.
- 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.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| TP-Link Systems Inc. | Tapo C520ws Firmware | < 1.2.4 | Vulnerable | NIST National Vulnerability Database |
| TP-Link Systems Inc. | Tapo C520WS v2.6 | < 1.2.4 Build 260326 Rel.24666n | Vulnerable | CVE Program (cve.org) e CISA ADP |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 7.1 | CVSS 4.0 | High | — | — | f23511db-6c3e-4e32-a477-6aa17d310630 via NIST National Vulnerability Database |
| 7.1 | CVSS 4.0 | High | — | — | TPLink via CVE Program (cve.org) e CISA ADP |
| 6.5 | CVSS 3.1 | Medium | 2.8 | 3.6 | nvd@nist.gov via NIST National Vulnerability Database |
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (score shown at the top: nvd@nist.gov) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
EPSS over time FIRST
Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.36%
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.
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · tp-link systems inc./tapo c520ws v2.6
- SSVC assessment updated
- Record published
- CVSS changed · 6.5
- Source status changed · → Analyzed
- Record created in this database
- CVE published
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
Related CVEs (same products)
- Medium CVE-2026-8714 Denial-of-Service Vulnerability in RTSP Input Handling on TP-Link's Tapo C520WS Jun 5, 2026
- Medium CVE-2026-34124 Denial of Service via Path Expansion Overflow in HTTP Service in TP-Link Tapo C520WS Apr 2, 2026
- Medium CVE-2026-34118 Heap-based Buffer Overflow Vulnerability Leading to Denial-of-Service in TP-Link Tapo C100, C101 & C520WS Apr 2, 2026
- Medium CVE-2026-34119 Heap-based Buffer Overflow Vulnerability Leading to Denial-of-Service in TP-Link Tapo C520WS Apr 2, 2026
- Medium CVE-2026-34120 Heap-based Buffer Overflow Vulnerability Leading to Denial-of-Service in TP-Link Tapo C520WS Apr 2, 2026
- High CVE-2026-34121 Authentication Bypass in DS Configuration Service via HTTP Request Parsing Differential of TP-Link Tapo C520WS Apr 2, 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-2026-34122 is "Stack-based Buffer Overflow Leading to Denial of Service in TP-Link Tapo C520WS", rated Medium. It affects Tapo C520ws Firmware (TP-Link Systems Inc.); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 6.5 describes technical severity. EPSS 0.36% 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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