CVE-2023-46250: Pypdf Possible Infinite Loop When PdfWriter(clone_from) Vulnerability

MODERATE
Advisory Identifier: GHSA-wjcc-cq79-p63f
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CVSS 5.1
CWE-835
Published
Advisory Summary

CVE-2023-46250 is a MODERATE (CVSS 5.1) possible infinite loop when pdfwriter(clone_from) vulnerability (CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop')) affecting Pypdf libraries in the PyPI ecosystem. The issue involves possible infinite loop when pdfwriter(clone_from) is used with a pdf. Remediation is available by upgrading affected packages to version 3.17.0.

CVE-2023-46250 at a Glance

CVE Identifier CVE-2023-46250
GHSA Identifier GHSA-wjcc-cq79-p63f
Severity MODERATE
CVSS v3.1 Base Score 5.1
CWE Classification CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop')
Affected Product Pypdf
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 5.1

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H).

Attack Vector Local (AV:L)
Attack Complexity High (AC:H)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity None (I:N)
Availability High (A:H)

How to Fix CVE-2023-46250

To remediate this vulnerability, upgrade all affected Pypdf dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

pypdf fixed: 3.17.0 
pip install pypdf>=3.17.0
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show pypdf

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2023-46250, inspect your installed packages using pip:

pip show pypdf

Analyze the terminal output to locate any version of Pypdf in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 3.17.0), your application is affected.

Note: The pip show pypdf command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop'), where the product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop. In Pypdf, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Impact An attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This infinite loop blocks the current process and can utilize a single core of the CPU by 100%. It does not affect memory usage. That is, for example, the case when the pypdf-user manipulates an incoming malicious PDF e.g. by merging it with another PDF or by adding annotations. ### Patches The issue was fixed with #2264 ### Workarounds If you cannot update your version of pypdf, you should modify `pypdf/generic/_data_structures.py` just like #2264 did.

CVE-2023-46250 Affected Pypdf Versions

1 component(s)
Fixed Versions:
3.17.0
Product / Package Ecosystem Affected Versions Fixed Version
pypdf
pypi/pypdf
PyPI
≥ 3.7.0
< 3.17.0
3.17.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/py-pdf/pypdf/security/advisories/GHSA-wjcc-cq79-p63f
NVD — CVE-2023-46250 NVD
https://nvd.nist.gov/vuln/detail/CVE-2023-46250
Pypdf Source Repository REPOSITORY
https://github.com/py-pdf/pypdf/pull/2264
Security Fix Commit FIX COMMIT
https://github.com/py-pdf/pypdf/commit/9b23ac3c9619492570011d551d521690de9a3e2d
Pypdf Source Repository REPOSITORY
https://github.com/py-pdf/pypdf

Frequently Asked Questions

What is CVE-2023-46250?
CVE-2023-46250 is a security vulnerability in Pypdf involving Possible Infinite Loop when PdfWriter(clone_from) is used with a PDF under CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop').
Which Pypdf versions are affected?
Affected versions include releases prior to 3.17.0 across affected packages: pypdf.
What version fixes CVE-2023-46250?
Upgrading to 3.17.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is pypdf affected?
Yes, pypdf is affected in releases prior to 3.17.0. Upgrade your dependency to 3.17.0 or later.
What is the CVSS score of CVE-2023-46250?
CVE-2023-46250 has a CVSS v3.1 base score of 5.1 (MODERATE) with vector string CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2023-46250?
CVE-2023-46250 is classified under CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop') (The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop.).
How can I check PyPI dependencies for CVE-2023-46250?
Run the dependency tree command: 'pip show pypdf'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-wjcc-cq79-p63f",
  "modified" : "2023-10-31T22:22:50Z",
  "published" : "2023-10-31T22:22:50Z",
  "aliases" : [ "CVE-2023-46250" ],
  "summary" : "Possible Infinite Loop when PdfWriter(clone_from) is used with a PDF",
  "details" : "### Impact\nAn attacker who uses this vulnerability can craft a PDF which leads to an infinite loop.\nThis infinite loop blocks the current process and can utilize a single core of the CPU by 100%. It does not affect memory usage.\n\nThat is, for example, the case when the pypdf-user manipulates an incoming malicious PDF e.g. by merging it with another PDF or by adding annotations.\n\n### Patches\nThe issue was fixed with #2264\n\n### Workarounds\nIf you cannot update your version of pypdf, you should modify `pypdf/generic/_data_structures.py` just like #2264 did.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "pypdf"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "3.7.0"
      }, {
        "fixed" : "3.17.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/py-pdf/pypdf/security/advisories/GHSA-wjcc-cq79-p63f"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2023-46250"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/py-pdf/pypdf/pull/2264"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/py-pdf/pypdf/commit/9b23ac3c9619492570011d551d521690de9a3e2d"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/py-pdf/pypdf"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-835" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2023-10-31T22:22:50Z",
    "nvd_published_at" : "2023-10-31T16:15:09Z"
  }
}