Cyber Resilience

CVE-2026-3622

Memory Safety in Tp-Link Tl-Wr841N Firmware ≤ 0.9.1_4.19

Memory Safety
Published
26 March 2026
Modified
31 March 2026
Patch / advisory
View advisory
CVSS Score v4 7.1
Click a component to see what it means
Raw vectorCVSS: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
EPSS Score 0.0036 28th percentile
Risk Priority 36 floored blend · peak EPSS

Summary

CVE-2026-3622 is a high-severity Out-of-bounds Read (CWE-125) vulnerability in Tp-Link Tl-Wr841N Firmware. Its CVSS base score is 7.1 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 28th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SA-8 (Security and Privacy Engineering Principles) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2026-3622 is a vulnerability in the UPnP component of TP-Link TL-WR841N v14 routers, stemming from improper input validation that triggers an out-of-bounds read (CWE-125). This flaw affects firmware versions prior to EN_0.9.1 4.19 Build 260303 Rel.42399n (V14_260303) for international models and US_0.9.1.4.19 Build 260312 Rel.49108n (V14_0304) for US models. The issue has a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H), highlighting its potential for high-impact availability disruption without requiring authentication or user interaction.

Attackers can exploit this vulnerability remotely over the network by sending malformed input to the UPnP service, causing an out-of-bounds read that crashes the service and results in a denial-of-service condition. No privileges are needed, and the low attack complexity makes it accessible to unauthenticated remote actors who can reach the device's UPnP interface, typically exposed if UPnP is enabled.

TP-Link advisories recommend updating to the specified firmware versions or later, available via their support download pages for TL-WR841N v14 (EN and US variants). Additional guidance is provided in their FAQ at https://www.tp-link.com/us/support/faq/5033/, which likely details patching and configuration steps to mitigate the issue.

EU & UK References

Vulnerability Data

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…

more

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).

CWE(s)
CWE-125

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
attack.mitre.org →
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
attack.mitre.org →
T1211 Exploitation for Stealth Stealth
Adversaries may exploit vulnerabilities to evade detection by hiding activity, suppressing logging, or operating within trusted or unmonitored components.
attack.mitre.org →
T1212 Exploitation for Credential Access Credential Access
Adversaries may exploit software vulnerabilities in an attempt to collect credentials.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-9105Same product: Tp-Link Tl-Wr841N
CVE-2025-53711Same product: Tp-Link Tl-Wr841N
CVE-2025-53714Same product: Tp-Link Tl-Wr841N
CVE-2025-53713Same product: Tp-Link Tl-Wr841N
CVE-2025-53712Same product: Tp-Link Tl-Wr841N
CVE-2025-53715Same product: Tp-Link Tl-Wr841N
CVE-2023-33536Same product: Tp-Link Tl-Wr841N
CVE-2023-33537Same product: Tp-Link Tl-Wr841N
CVE-2023-36356Same product: Tp-Link Tl-Wr841N
CVE-2025-9014Same product: Tp-Link Tl-Wr841N

Affected Assets

tp-link
tl-wr841n firmware
≤ 0.9.1_4.19

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

SA-11 Developer Testing and Evaluation good match

Developer testing and evaluation directly finds out-of-bounds read flaws through static analysis, fuzzing, and dynamic bounds checks.

SA-8 Security and Privacy Engineering Principles partial match

Secure engineering principles require bounds checking and memory-safe constructs that stop out-of-bounds reads from being introduced.

SC-39 Process Isolation partial match

Process isolation confines the effects of an out-of-bounds read to the compromised process.

SI-10 Information Input Validation partial match

Input validation rejects malformed indices or lengths that would otherwise cause reads outside buffer bounds.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure-development practices such as bounds checking and memory-safe languages directly prevent out-of-bounds reads.

ID.RA-01 partial match
prevents

Vulnerability scanning and recording can discover instances of out-of-bounds reads after code is deployed.

PR.PS-02 partial match
prevents

Routine patching replaces vulnerable code containing out-of-bounds read flaws.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing in development and acceptance includes fuzzing and static analysis that detect out-of-bounds read defects before release.

A.8.15 Logging partial match
finds

Logging can record evidence of an out-of-bounds read but does not prevent the weakness itself.

A.8.25 Secure development life cycle partial match
prevents

Secure development life cycle mandates input validation and bounds checking that directly prevent out-of-bounds reads.

A.8.26 Application security requirements partial match
prevents

Application security requirements include explicit bounds and memory-safety specifications that mitigate buffer over-reads.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure system architecture and engineering principles require memory-safe design patterns and runtime protections against out-of-bounds access.

A.8.28 Secure coding partial match
prevents

Secure coding standards explicitly forbid unsafe pointer arithmetic and mandate bounds-checked reads, eliminating CWE-125.

References