CVE intelligence and bounded remediation

CVE-2020-25708 — A divide by zero issue was found to occur in libvncserver-0.9.12

High CVSS 7.5

A divide by zero issue was found to occur in libvncserver-0.9.12. A malicious client could use this flaw to send a specially crafted message that, when processed by the VNC server, would lead to a floating point exception, resulting in a denial of service.

Severity
High
CVSS
7.5 (3.1)
Published
2020-11-27
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-369

Affected products

  • libvncserver_project / libvncserver / 0.9.12
  • redhat / enterprise_linux / 6.0
  • redhat / enterprise_linux / 7.0
  • redhat / enterprise_linux / 8.0
  • debian / debian_linux / 10.0

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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