CVE intelligence and bounded remediation

CVE-2021-28700 — Xen Xen security vulnerability

Medium CVSS 6.8

xen/arm: No memory limit for dom0less domUs The dom0less feature allows an administrator to create multiple unprivileged domains directly from Xen. Unfortunately, the memory limit from them is not set. This allow a domain to allocate memory beyond what an administrator originally configured.

Severity
Medium
CVSS
6.8 (2.0)
Published
2021-08-27
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-770

Affected products

  • xen / xen
  • fedoraproject / fedora / 33
  • fedoraproject / fedora / 34
  • fedoraproject / fedora / 35
  • debian / debian_linux / 11.0

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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