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Tl Wr841n FirmwareOperating system · Tp Link

CVE-2026-3622

HIGH · 7.5 CVSS v3.1 Published 2026-03-26
Fix available
A fix is available. Upgrade to 0.9.1_4.19 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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).

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A high-severity out-of-bounds read vulnerability exists in the UPnP service of TP-Link TL-WR841N v14 routers due to improper input validation. The flaw allows remote attackers to trigger a crash of the UPnP daemon, resulting in denial of service.

MitigationUpdate the router firmware to the patched version (EN_0.9.1 4.19 Build 260303 or US_0.9.1.4.19 Build 260312 and above). If no patched firmware is available, disable UPnP functionality in the router settings as a temporary workaround.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Tl Wr841n FirmwareOperating system
Affected:< 0.9.1_4.19

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Confirm router model
    Access the router web interface (typically at 192.168.0.1 or 192.168.1.1) and check the device model number in the status or system information page. Alternatively, check the physical device label for 'TL-WR841N' and look for 'v14' marking.
    Affected if The router is not a TP-Link TL-WR841N v14, the vulnerability does not apply.
  2. Check installed firmware version
    In the router web interface, navigate to System Tools > Firmware Upgrade or Status page. The current firmware version is displayed there. Compare it to the affected version range: any version before 0.9.1_4.19 (including EN_0.9.1 4.19 Build 260303 or US_0.9.1.4.19 Build 260312) is vulnerable.
    Affected if The installed firmware version is less than 0.9.1_4.19.
  3. Verify UPnP service status
    In the router web interface, go to Forwarding > UPnP or Advanced > UPnP settings. Check whether the UPnP function is enabled or turned on.
    Affected if UPnP is enabled - this is the condition required for the out-of-bounds read flaw to be exploitable.

The router is affected if it is a TL-WR841N v14 model running firmware version below 0.9.1_4.19 AND has UPnP functionality enabled.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 0.9.1_4.19 or later
Fixed in 0.9.1_4.19
Interim mitigation

Update the router firmware to the patched version (EN_0.9.1 4.19 Build 260303 or US_0.9.1.4.19 Build 260312 and above). If no patched firmware is available, disable UPnP functionality in the router settings as a temporary workaround.

Recommended fix High confidence

TL-WR841N v14 firmware 0.9.1_4.19 (EN_0.9.1 4.19 Build 260303 Rel.42399n or US_0.9.1.4.19 Build 260312 Rel.49108n)

  1. Navigate to the official TP-Link support website (www.tp-link.com)
  2. Locate the TL-WR841N v14 product page and go to the Firmware section
  3. Download the EN_0.9.1 4.19 Build 260303 Rel.42399n (V14_260303) firmware for EU models, or US_0.9.1.4.19 Build 260312 Rel.49108n (V14_0304) for US models
  4. Access the router's web management interface (typically at 192.168.0.1 or 192.168.1.1)
  5. Navigate to System Tools > Firmware Upgrade (or similar path)
  6. Upload the downloaded firmware file and initiate the upgrade
  7. Wait for the upgrade to complete and the router to reboot automatically
  8. Verify the firmware version has been updated to 0.9.1_4.19 or later in the router status page
Caveat Standard router firmware upgrade may reset configuration to defaults; back up existing settings before upgrading if needed

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Tl Wr841n Firmware Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,420
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-3622 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data