CVE-2025-8138: A vulnerability was found in TOTOLINK A702R 4.0.0-B20230721.1521 and classified as critical. Affected by this issue is some unknown functionality of the file…

PriorityP269high8.8CVSS 3.1

AVNACLPRLUINSUCHIHAH

EPSS

7.10%

93.5th percentile

A vulnerability was found in TOTOLINK A702R 4.0.0-B20230721.1521 and classified as critical. Affected by this issue is some unknown functionality of the file /boafrm/formOneKeyAccessButton of the component HTTP POST Request Handler. The manipulation of the argument submit-url leads to buffer overflow. The attack may be launched remotely. The exploit has been disclosed to the public and may be used.

Affected

2 ranges

Vendor	Product	Version range	Fixed in
totolink	a702r	—	—
totolink	a702r_firmware	—	—

Detection & IOCsextracted from sources · hover to see the quote

path/boafrm/formOneKeyAccessButton↗

snort

alert http any any -> $HOME_NET any (msg:"ET WEB_SPECIFIC_APPS Totolink formOneKeyAccessButton submit-url Parameter Buffer Overflow Attempt (CVE-2025-8138)"; flow:established,to_server; http.method; content:"POST"; http.uri; bsize:30; content:"/boafrm/formOneKeyAccessButton"; fast_pattern; http.request_body; content:"submit-url|3d|"; pcre:"/^[^\x26$]{100,}(?:\x26|$)/R"; reference:url,github.com/panda666-888/vuls; reference:cve,2025-8138; classtype:web-application-attack; sid:2063743; rev:1; metadata:affected_product TOTOLINK, attack_target Networking_Equipment, tls_state plaintext, created_at 2025_07_25, cve CVE_2025_8138, deployment Perimeter, deployment Internal, performance_impact Low, confidence High, signature_severity Major, tag Exploit, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2025_07_25, mitre_tactic_id TA0001, mitre_tactic_name Initial_Access, mitre_technique_id T1190, mitre_technique_name Exploit_Public_Facing_Application; target:dest_ip;)

→Exploit targets HTTP POST requests to /boafrm/formOneKeyAccessButton; match on POST method combined with this exact URI (bsize:30 — no trailing characters).
→Buffer overflow is triggered via the submit-url parameter in the POST body; look for 'submit-url=' (URL-encoded as 'submit-url|3d|') followed by 100 or more non-ampersand characters, indicating an oversized value.
→Attack is plaintext (non-TLS); deploy detection at perimeter and internal network boundaries targeting inbound traffic to networking equipment.
→MITRE mapping: Initial Access (TA0001) via Exploit Public-Facing Application (T1190); prioritize internet-exposed TOTOLINK A702R devices running firmware 4.0.0-B20230721.1521.

·Affected firmware version is specifically TOTOLINK A702R 4.0.0-B20230721.1521; detections should be scoped to this device/version to reduce false positives. ↗
·The Snort/Suricata rule (sid:2063743) uses a PCRE match on the request body; ensure the IDS engine supports the /R (relative) PCRE modifier and that HTTP body inspection is enabled for accurate detection.
·The exploit has been publicly disclosed; a public PoC repository is referenced, meaning weaponized exploit code is likely available and exploitation attempts may be imminent. ↗

CVSS provenance

nvdv3.18.8HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

nvdv4.07.4HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/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

nvdv2.09.0CRITICALAV:N/AC:L/Au:S/C:C/I:C/A:C

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