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CVE-2026-119205high7.1

pypdf: Possible infinite loop when cloning dictionaries

Impact

pypdf versions before 6.21.4 may enter an infinite loop when cloning dictionaries, potentially caused by an attacker crafting a malicious PDF. The vulnerability requires cloning a DictionaryObject.

Summarized by @cf/meta/llama-3.3-70b-instruct-fp8-fast. Verify details against the original sources.
Applies when

This requires cloning/duplicating a DictionaryObject.

Affected packages

Start with the recorded fix for your release branch. Check your installed version and test compatibility before upgrading. Fixing this advisory does not rule out other vulnerabilities in the release.

pypdf PyPI
Affected range Recorded fix
Earlier releases before 6.21.4Ecosystem versions6.21.4

Version evidence: OSV · GHSA-mfr5-77xh-9j7h

View original version evidence (126 explicit versions)

Affected products

Vendor version evidence. Product records are separate from automatic dependency matching.

py-pdf · GitHub_M

pypdf

1 range
GitHub_M version evidence

Compare with this publisher’s ranges. This does not inspect your installation.

affected

< 6.21.4

unaffected

unknown

Other versions: unknown

Original source description

Impact

An attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires cloning/duplicating a DictionaryObject.

Patches

This has been fixed in pypdf==6.21.4.

Workarounds

If you cannot upgrade yet, consider applying the changes from PR #4288.

Inside the record

Evidence available

Package identity
Version evidence
Remediation guidance · not supplied
Weakness classification
Additional publishers

Describes the evidence in this view, not whether the product is safe.

Original records

CVE-2026-119205

View the latest unmodified CVE JSON from the official source. It may be newer than this imported page.

cve.new JSON →

Underlying weaknesses

The source’s classification of what caused the vulnerability.

CWE-835 ↗

CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop')

GitHub_M

Related →
Contributing organizations · 2
GitHub_M

Assigning organization

2026-10-29
CISA-ADP

Additional data publisher

2026-10-30

What changed

Follow changes
  1. CVE · CVE-2026-119205

    Observed 2026-10-30T17:29:35.255Z · upstream updated 2026-10-30T16:00:42.997Z

    Prioritization updated

    before

    []

    after

    [
  {
    "source": "CISA-ADP",
    "type": "SSVC",
    "role": "CISA Coordinator",
    "timestamp": "2026-10-30T15:47:20.322109Z",
    "decisions": [
      {
        "name": "Exploitation",
        "value": "none"
      },
      {
        "name": "Automatable",
        "value": "yes"
      },
      {
        "name": "Technical Impact",
        "value": "partial"
      }
    ]
  }
]

Large field values are marked as truncated previews. Original source snapshots remain retained.

Showing up to 50 most recent observed changes.

References

6 sources
github.com/py-pdf/pypdf/security/advisories/GHSA-mfr5-77xh-9j7h
Security advisoryGitHub_M
github.com/py-pdf/pypdf/pull/4288
PatchGitHub_M
github.com/py-pdf/pypdf/commit/f176db1a1f7f9af3e472e69a843ef1175653b044
PatchGitHub_M
github.com/py-pdf/pypdf/releases/tag/6.21.4
Release notesGitHub_M
nvd.nist.gov/vuln/detail/CVE-2026-119205
Security advisory
github.com/py-pdf/pypdf
Source reference