CVE intelligence and bounded remediation

CVE-2026-48156 — pypdf is a free and open-source pure-python PDF library

Medium CVSS 5.1

pypdf is a free and open-source pure-python PDF library. Prior to 6.12.0, an attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires cross-reference streams with /W [0 0 0] values and large /Size values. This vulnerability is fixed in 6.12.0.

Severity
Medium
CVSS
5.1 (4.0)
Published
2026-05-28
CISA KEV
Not currently listed
Ecosystem
python/pypi
Weaknesses
CWE-834

Affected products

  • pypdf_project / pypdf

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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