CVE-2025-10838: A vulnerability was identified in Tenda AC21 16.03.08.16. The affected element is the function sub_45BB10 of the file /goform/WifiExtraSet. The manipulation of…

PriorityP263high8.8CVSS 3.1

AVNACLPRLUINSUCHIHAH

EPSS

0.95%

57.7th percentile

A vulnerability was identified in Tenda AC21 16.03.08.16. The affected element is the function sub_45BB10 of the file /goform/WifiExtraSet. The manipulation of the argument wpapsk_crypto leads to buffer overflow. It is possible to initiate the attack remotely. The exploit is publicly available and might be used.

Affected

2 ranges

Vendor	Product	Version range	Fixed in
tenda	ac21	—	—
tenda	ac21_firmware	<= 16.03.08.16	—

Detection & IOCsextracted from sources · hover to see the quote

url/goform/WifiExtraSet↗

snort

alert http any any -> $HOME_NET any (msg:"ET WEB_SPECIFIC_APPS Tenda WifiExtraSet wpapsk_crypto Parameter Buffer Overflow Attempt (CVE-2025-25663, CVE-2025-10838, CVE-2025-7596, CVE-2025-5799)"; flow:established,to_server; http.method; content:"POST"; http.uri; bsize:20; content:"/goform/WifiExtraSet"; fast_pattern; http.request_body; content:"wpapsk_crypto|3d|"; pcre:"/^[^&]{100,}(?:&|$)/R"; reference:cve,2025-10838; reference:url,community.emergingthreats.net/t/ruleset-update-summary-2025-10-14-v11039/3081; reference:cve,2025-25663; reference:url,www.cve.org/CVERecord/SearchResults?query=wpapsk_crypto; reference:cve,2025-5799; reference:cve,2025-7596; classtype:web-application-attack; sid:2065201; rev:1; metadata:affected_product Tenda, attack_target Networking_Equipment, tls_state plaintext, created_at 2025_10_15, cve CVE_2025_5799_CVE_2025_10838_CVE_2025_7596_CVE_2025_25663, deployment Perimeter, deployment Internal, performance_impact Low, confidence High, signature_severity Major, tag Exploit, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2025_10_15, mitre_tactic_id TA0001, mitre_tactic_name Initial_Access, mitre_technique_id T1190, mitre_technique_name Exploit_Public_Facing_Application; target:dest_ip;)

→Look for HTTP POST requests to the exact URI /goform/WifiExtraSet (URI length is exactly 20 bytes) targeting Tenda AC21 devices.
→Inspect the POST request body for the parameter 'wpapsk_crypto=' (encoded as wpapsk_crypto|3d|) followed by a value of 100 or more characters before an '&' or end of body — indicative of a buffer overflow attempt.
→The exploit is delivered over plaintext HTTP (not TLS); perimeter and internal deployment points are both relevant for detection.
→The attack maps to MITRE ATT&CK T1190 (Exploit Public-Facing Application) under tactic TA0001 (Initial Access); prioritize detection on internet-exposed Tenda networking equipment.
→A public exploit is available; treat any matching traffic as high-confidence and high-severity. ↗

·The vulnerable function is sub_45BB10 in firmware version 16.03.08.16 only; confirm the firmware version of the target device before concluding exploitation. ↗
·The Snort/Suricata rule (ET sid:2065201) also covers three related CVEs (CVE-2025-25663, CVE-2025-7596, CVE-2025-5799) sharing the same wpapsk_crypto attack surface; a single alert may correspond to any of these CVEs.

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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