Tenda AC21 SetStaticRouteCfg sscanf buffer overflow

published 2025-09-28 13 mo ago modified 2026-10-09 30 d ago also EUVD-2025-31447

cvss: 8.8; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.8%; EPSS 0.8% chance of exploitation in 30 days, percentile 56%
public exploits: 0; none known

A security flaw has been discovered in Tenda AC21 up to 16.03.08.16. Affected by this vulnerability is the function sscanf of the file /goform/SetStaticRouteCfg. The manipulation of the argument list results in buffer overflow. The attack can be launched remotely. The exploit has been released to the public and may be exploited.

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: total
Assessed: 13 mo ago (2025-09-29)

Exploit prediction

0.78% chance of exploitation in the next 30 days, higher than 56% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/maximdevere/CVE2/issues/2 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	4.0	8.7	CVSS: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
CNA	3.1	8.8	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:X/RC:R
CNA	3.0	8.8	CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:X/RC:R
CNA	2.0	9.0	AV:N/AC:L/Au:S/C:C/I:C/A:C/E:POC/RL:ND/RC:UR
CNA	4.0	7.4	CVSS: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
CNA	3.1	8.8	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CNA	2.0	9.0	AV:N/AC:L/Au:S/C:C/I:C/A:C

Affected products

Tenda AC21

Classification

Weakness

CWE-120 Buffer Copy without Checking Size of Input
CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer

References

github.com /maximdevere/CVE2/issues/2
exploit, issue-tracking
vuldb.com /?id.326173
vdb-entry, technical-description, third-party-advisory
vuldb.com /?ctiid.326173
signature, permissions-required, vdb-entry
vuldb.com /?submit.661806
third-party-advisory, vdb-entry
tenda.com.cn /
product

Sources

CVE List CVE-2025-11091
NVD CVE-2025-11091

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary