CVE-2021-31755: Tenda AC11 Router Stack Buffer Overflow Vulnerability
Vulnerability summary
CVE-2021-31755 is a high (CVSS 10.0) Out-of-bounds Write vulnerability in Tenda AC11 Router. It is known to be exploited: CISA lists it, first on 03-11-2021. EPSS estimates a 86.51% chance of exploitation in the next 30 days, higher than 99.7% of scored vulnerabilities. 1 public exploit is recorded.
Timeline
- 07-05-2021PublishedVulnerability first disclosed.
- 03-11-2021Added to CISA KEVTenda AC11 Router Stack Buffer Overflow Vulnerability
- 17-11-2021CISA remediation dueApply updates per vendor instructions.
- 21-10-2025Last modifiedVulnerability information updated.
Description
An issue was discovered on Tenda AC11 devices with firmware through 02.03.01.104_CN. A stack buffer overflow vulnerability in /goform/setmac allows attackers to execute arbitrary code on the system via a crafted post request.
CVSS metrics
3 scores · 2 sources · 2 versions- NVDNIST9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
86.51%
Chance of exploitation in the next 30 days
Percentile
100%
Versus all other CVEs
30-day change
-0.38 pp
From 86.89% on 22-09-2026
Known exploited
Compare KEV catalogs
CISA KEVListed- Added
- 03-11-2021
- Federal due date
- 17-11-2021
CISA required action
Apply updates per vendor instructions. nvd.nist.gov/vuln/detail/CVE-2021-31755
Public exploits
1 foundIot Cve
Maturity: poc
Weaknesses
CWE · root causeAffected systems
Tenda1 product
- ac11_firmware≤ 02.03.01.104_cn
1 vendor · 1 product
References
2 links- github.com/Yu3H0/IoT_CVE/tree/main/Tenda/CVE_3X Refsource MISCBroken LinkExploitIssue TrackingThird Party Advisory
- www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-31755Government ResourceUS Government Resource