CVE-2026-17251

Unauthenticated HTTP service crash via malformed cookie

Published Aug 21, 2026 · Updated Aug 21, 2026

NULL pointer dereference in TP-Link TL-MR6400 v7 before 1.9.0 Build 260714 allows remote attackers to crash the HTTP service. The HTTP request parser dereferences a NULL pointer while processing a malformed session cookie header in a crafted request. Attackers need adjacent-network access but no authentication or user interaction; a successful request temporarily disables management and CGI functions until the service recovers.

CVSS severity7.1
High
EPSS probability0.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in TP-Link TL-MR6400 v7 before 1.9.0 Build 260714 allows remote attackers to crash the HTTP service. The HTTP request parser dereferences a NULL pointer while processing a malformed session cookie header in a crafted request. Attackers need adjacent-network access but no authentication or user interaction; a successful request temporarily disables management and CGI functions until the service recovers.

The record

CVE
CVE-2026-17251
Published
Aug 21, 2026
Updated
Aug 21, 2026
Vendor
TP-Link Systems Inc.
Product
TL-MR6400
Classifications
CWE-476, T1499.004
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 21, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 21, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <1.9.0 Build 260714

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

TP-Link Systems Inc. · TL-MR6400version=0 <1.9.0 Build 260714

Published CVSS scores

7.1TPLinkCVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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