Buffer overflow in Tenda Ac21
CVE-2026-1637
A vulnerability was identified in Tenda AC21 16.03.08.16. The affected element is the function fromAdvSetMacMtuWan of the file /goform/AdvSetMacMtuWan. The manipulation leads to stack-based buffer overflow. Remote exploitation of the attack is possible. The exploit is publicly available and might be used.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.007 (51.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 52nd percentile — 51.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: +0.001
Affected products
- Tenda Ac21 — versions 16.03.08.16
- Tenda Ac21 Firmware — versions 16.03.08.16
Weakness classification (CWE)
References
- vuldb.com/ (technical-description, VDB Entry, Third Party Advisory, vdb-entry)
- vuldb.com/ (signature, Permissions Required, permissions-required, VDB Entry)
- vuldb.com/ (VDB Entry, Third Party Advisory, third-party-advisory)
- github.com/LX-LX88/cve/issues/25 (issue-tracking, exploit, broken-link, Broken Link)
- www.tenda.com.cn/ (Product, product)
Frequently asked questions
- What is CVE-2026-1637?
- CVE-2026-1637 is a high-severity vulnerability in Tenda Ac21, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 8.8/10. Published 2026-01-29.
- How severe is CVE-2026-1637?
- High severity. CVSS v3 base score is 8.8 out of 10.