CVE intelligence and bounded remediation

CVE-2021-28846 — Trendnet Tew-755Ap Firmware security vulnerability

Medium CVSS 6.5

A Format String vulnerablity exists in TRENDnet TEW-755AP 1.11B03, TEW-755AP2KAC 1.11B03, TEW-821DAP2KAC 1.11B03, and TEW-825DAP 1.11B03, which could let a remote malicious user cause a denial of service due to a logic bug at address 0x40dcd0 when calling fprintf with "%s: key len = %d, too long\n" format. The two variables seem to be put in the wrong order. The vulnerability could be triggered by sending the POST request to apply_cgi with a long and unknown key in the request body.

Severity
Medium
CVSS
6.5 (3.1)
Published
2021-08-10
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-134

Affected products

  • trendnet / tew-755ap_firmware / 1.11b03
  • trendnet / tew-755ap2kac_firmware / 1.11b03
  • trendnet / tew-821dap2kac_firmware / 1.11b03
  • trendnet / tew-825dap_firmware / 1.11b03

Matched remediation archetype

Resource exhaustion and denial of service

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Identify attacker-influenced work factors including input size, nesting, compression, fan-out, regex cost, allocation, recursion, retries, and connection lifetime.
  • Map per-request and shared CPU, memory, disk, descriptor, thread, queue, and downstream-service limits.
  • Determine whether authentication, tenancy, quotas, and rate controls apply before expensive processing begins.

Remediate safely

  • Bound input size, nesting, expansion, work, concurrency, queue depth, retries, and execution time before resource-intensive processing.
  • Release resources on every success, error, cancellation, and timeout path and use backpressure instead of unbounded buffering.
  • Update affected components and add small deterministic tests that assert resource ceilings rather than exhausting a host.

Authoritative sources

Complete CVE record and remediation plan

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