CVE intelligence and bounded remediation

CVE-2020-12885 — An infinite loop was discovered in the CoAP library in Arm Mbed OS 5.15.3

High CVSS 7.8

An infinite loop was discovered in the CoAP library in Arm Mbed OS 5.15.3. The CoAP parser is responsible for parsing received CoAP packets. The function sn_coap_parser_options_parse_multiple_options() parses CoAP options in a while loop. This loop's exit condition is computed using the previously allocated heap memory required for storing the result of parsing multiple options. If the input heap memory calculation results in zero bytes, the loop exit condition is never met and the loop is not terminated. As a result, the packet parsing function never exits, leading to resource consumption.

Severity
High
CVSS
7.8 (2.0)
Published
2020-06-18
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-835

Affected products

  • arm / mbed_os / 5.15.3

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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