HIGH
CVE-2021-31627
CWE-120Published: October 29, 2021· Updated: Jul 9, 2026
8.8
CVSS v3.1
Official Description
Buffer Overflow vulnerability in Tenda AC9 V1.0 through V15.03.05.19(6318), and AC9 V3.0 V15.03.06.42_multi, allows attackers to execute arbitrary code via the index parameter.
Technical Analysis
CVE-2021-31627 requires adjacent network access, limiting remote exploitation but still posing risk in shared or local network environments.
The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.
A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 8.8.
CVSS v3.1 Vector Breakdown
Exploitability
Attack VectorAdjacent
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Affected Vendors & Products
tendacn2 product(s)
ac9 firmwareac9
Source: NVD CPE · 3 total CPE entries
Exploit & PoC Resources
NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.
Official Patches & Advisories
All References (2)
→
https://github.com/Lyc-heng/routers/blob/main/routers/stack3.mdExploit · Third Party Advisory
→
https://github.com/Lyc-heng/routers/blob/main/routers/stack3.mdExploit · Third Party Advisory
Quick Facts
CVE IDCVE-2021-31627
CVSS Score8.8 / 10
SeverityHIGH
WeaknessCWE-120
CISA KEVNo
Affected1 vendor(s)
PublishedOct 29, 2021
Related CVEs (CWE-120)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2021-31627 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.