Quick answer
Direct answer
Risk scores
| CVSS metric | What it means |
|---|---|
| Attack vector (AV:A) | Adjacent network |
| Attack complexity (AC:L) | Low complexity |
| Attack requirements (AT:N) | No attack requirements |
| Privileges required (PR:N) | No privileges required |
| User interaction (UI:N) | No user interaction |
| Confidentiality (VC:N) | No confidentiality impact |
| Integrity (VI:N) | No integrity impact |
| Availability (VA:H) | High availability impact |
CVSS:4.0/AV:A/AC:L/AT:N/PR:N/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
About Tp-Link Tl-Wr841n Firmware
CVE-2026-3622 affects Tp-Link Tl-Wr841n Firmware, a product from Tp-Link. Before acting, confirm where Tp-Link Tl-Wr841n Firmware runs in your estate, who owns it and whether it is reachable from the internet, because exposure decides real risk more than the score alone.
What the flaw is
In plain terms: The vulnerability exists in the UPnP component of TL-WR841N v14, where improper input validation leads to an out-of-bounds read, potentially causing a crash of the UPnP service. Successful exploitation can cause the UPnP service to crash, resulting in a Denial-of-Service condition. This vulnerability affects TL-WR841N v14 < EN_0.9.1 4.19 Build 260303 Rel.42399n (V14_260303) and < US_0.9.1.4.19 Build 260312 Rel. 49108n (V14_0304).
The weakness class is Out of Bounds Read. The program reads memory past the end of a buffer, leaking data or crashing.
Based on its CVSS vector, the flaw needs local or adjacent access, needs no login, and needs no user interaction. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.
Affected versions and timeline
| Field | Detail |
|---|---|
| Product | Tp-Link Tl-Wr841n Firmware |
| Affected versions | Tl-Wr841n Firmware before 0.9.1_4.19 |
| Published | Mar 26, 2026 |
| Last modified | Jun 17, 2026 |
| Added to CISA KEV | Not listed |
| Assigning CNA | f23511db-6c3e-4e32-a477-6aa17d310630 |
How to detect it
- Inventory every instance of Tp-Link Tl-Wr841n Firmware and record the running version against the affected range above.
- Check external attack surface scans for internet facing instances of the component.
- Review logs on affected systems for unusual requests, errors or new processes around the vulnerable function.
- Confirm with an authenticated vulnerability scan once your scanner has a check for this CVE.
How to fix it
- Apply the fixed version of Tp-Link Tl-Wr841n Firmware named in the vendor advisory.
- If patching must wait, restrict network access to the affected service and put it behind authentication or a web application firewall rule.
- Rescan after the change to prove the exposure is gone, then close the ticket.
CTEM action plan
| CTEM stage | What to do for this CVE |
|---|---|
| Scope | Add every business service that depends on Tp-Link Tl-Wr841n Firmware to the current CTEM cycle. |
| Discover | Find all instances, including shadow and cloud deployments, and record versions and exposure. |
| Prioritize | Rank using EPSS and CVSS together with asset exposure and business impact. |
| Validate | Confirm the flaw is reachable and exploitable in your environment and that compensating controls work. |
| Mobilize | Assign the fix to the asset owner with a due date matched to the priority, then verify closure. |
CWE References
- CWE-125: Out of Bounds Read More CVEs with this weakness
Technical References
Frequently asked questions
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