CVE-2026-76651: Pre-Authentication Multipart Boundary Buffer Overflow in HTTP Service in TP-Link TL-WR841N

Severity: medium (CVSS 5.3 v4.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-28 · updated 2026-09-01
Weakness: CWE-120

Description

A buffer overflow vulnerability exists in the embedded HTTP service in TL-WR841N v14 when processing multipart/form-data requests. Insufficient validation of an attacker-controlled boundary parameter may allow a remote unauthenticated attacker to submit a crafted request that corrupts memory by overwriting data beyond the bounds of an internal buffer. Successful exploitation may result in modification or corruption of process memory, potentially leading to undefined application behavior. Arbitrary code execution, information disclosure, and denial-of-service conditions have not been demonstrated.

Affected products

TP-Link System Inc. TL-WR841N v14: before TL-WR841N(US)_V14_4.19 Build 260820 Rel.33478; before TL-WR841N(EU)_V14_4.19 Build 260821 Rel.56588 — fixed in TL-WR841N(EU)_V14_4.19 Build 260821 Rel.56588, TL-WR841N(US)_V14_4.19 Build 260820 Rel.33478

How to fix

Upgrade to a fixed version: TP-Link System Inc. TL-WR841N v14 TL-WR841N(EU)_V14_4.19 Build 260821 Rel.56588, TL-WR841N(US)_V14_4.19 Build 260820 Rel.33478. Check the vendor advisory for mitigations.

References

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