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PatchSiren cyber security CVE debrief

CVE-2021-31755 Tenda CVE debrief

CVE-2021-31755 is a Tenda AC11 Router stack buffer overflow vulnerability that CISA added to its Known Exploited Vulnerabilities catalog on 2021-11-03, with a remediation due date of 2021-11-17. The supplied authoritative sources identify the issue and the need to apply vendor-provided updates, but do not provide additional technical detail in this corpus.

Vendor
Tenda
Product
AC11 Router
CVSS
Unknown
CISA KEV
Listed
Original CVE published
2021-11-03
Original CVE updated
2021-11-03
Advisory published
2021-11-03
Advisory updated
2021-11-03

Who should care

Organizations that use or manage Tenda AC11 Routers, especially security teams, network administrators, and asset owners responsible for internet-facing or internally managed network devices.

Technical summary

The available official records describe CVE-2021-31755 as a stack buffer overflow in the Tenda AC11 Router. CISA’s KEV entry marks it as known exploited and directs defenders to apply updates per vendor instructions. No further exploit mechanics, impact details, or CVSS score are provided in the supplied source corpus.

Defensive priority

High. The vulnerability is listed in CISA’s KEV catalog, which indicates confirmed exploitation and a short remediation window in the provided timeline.

Recommended defensive actions

  • Inventory all Tenda AC11 Router deployments and confirm exposure.
  • Apply vendor-provided updates or mitigations as directed by Tenda and CISA.
  • Prioritize remediation for any internet-facing or business-critical devices.
  • Verify firmware versions after patching and document completion.
  • Monitor CISA KEV updates and vendor advisories for related guidance.

Evidence notes

This debrief is based only on the supplied official sources: CISA KEV metadata, the CVE record, and the NVD detail link referenced by CISA. The corpus confirms the product, vulnerability name, KEV status, date added (2021-11-03), due date (2021-11-17), and the instruction to apply vendor updates. No unsupported impact or exploitation specifics were added.

Sources and references

Verified primary and authoritative sources

  • CVE-2021-31755 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2021-31755

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2021-31755 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2021-31755

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

  • CISA Known Exploited Vulnerabilities catalog

    Publisher, destination, and source semantics verified

    URL: https://www.cisa.gov/known-exploited-vulnerabilities-catalog

    Cybersecurity and Infrastructure Security Agency - Official CISA catalog of vulnerabilities known to be exploited in the wild.

Supplemental references

  • Source item URL

    Unverified legacy reference

    URL: https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json

    cisa_kev

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.