CVE-2025-15255Public exploitNetwork attack vector

Pre-authentication execution-flow hijack via unbounded Cookie parsing

Published Dec 30, 2025 · Updated Dec 30, 2025

Stack-based buffer overflow in Tenda W6-S 1.0.0.4(510) allows remote attackers to hijack execution via a crafted Cookie header. The pre-authentication R7websSecurityHandler path in /bin/httpd uses sscanf to copy the Cookie user value up to a semicolon without bounding the destination stack buffer. Any reachable HTTP endpoint processes the value before authentication or session checks, permitting a crash or attacker-controlled execution flow.

CVSS severity9.8
Critical
EPSS probability4.55%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack-based buffer overflow in Tenda W6-S 1.0.0.4(510) allows remote attackers to hijack execution via a crafted Cookie header. The pre-authentication R7websSecurityHandler path in /bin/httpd uses sscanf to copy the Cookie user value up to a semicolon without bounding the destination stack buffer. Any reachable HTTP endpoint processes the value before authentication or session checks, permitting a crash or attacker-controlled execution flow.

The record

CVE
CVE-2025-15255
Published
Dec 30, 2025
Updated
Dec 30, 2025
Vendor
Shenzhen Tenda Technology Co., Ltd.
Product
W6-S 300Mbps in-wall Wireless Access Point
Classifications
CWE-121, CWE-119, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 30, 2025CVE publishedPublication date reported by the CVE source.
  2. Dec 30, 2025Record 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=1.0.0.4(510)

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Shenzhen Tenda Technology Co., Ltd. · W6-S 300Mbps in-wall Wireless Access Pointversion=1.0.0.4(510)

Published CVSS scores

10.0VulDBAV:N/AC:L/Au:N/C:C/I:C/A:C
9.8VulDBCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
8.9VulDBCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

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

Weakness, pattern, technique

CWE-121Stack-based Buffer Overflow
CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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