CVE-2026-48735: pypdf Manipulated XMP Metadata Streams Can Vulnerability

MODERATE
Advisory Identifier: GHSA-wjqc-6w8f-h24c
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CWE-770
Published
Advisory Summary

CVE-2026-48735 is a MODERATE manipulated xmp metadata streams can vulnerability (CWE-770: Allocation of Resources Without Limits or Throttling) affecting pypdf libraries in the PyPI ecosystem. The issue involves manipulated xmp metadata streams can exhaust ram. Remediation is available by upgrading affected packages to version 6.12.1.

CVE-2026-48735 at a Glance

CVE Identifier CVE-2026-48735
GHSA Identifier GHSA-wjqc-6w8f-h24c
Severity MODERATE
CVSS v3.1 Base Score N/A
CWE Classification CWE-770: Allocation of Resources Without Limits or Throttling
Affected Product pypdf
Package Ecosystem PyPI
Published Date
Last Updated

How to Fix CVE-2026-48735

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: 6.12.1 
pip install pypdf>=6.12.1
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-2026-48735, 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 6.12.1), 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-770: Allocation of Resources Without Limits or Throttling, where the product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated. 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 large memory usage. This requires parsing large XMP metadata, possibly with lots of unnecessary elements. ### Patches This has been fixed in [pypdf==6.12.1](https://github.com/py-pdf/pypdf/releases/tag/6.12.1). ### Workarounds If you cannot upgrade yet, consider applying the changes from PR [#3796](https://github.com/py-pdf/pypdf/pull/3796).

CVE-2026-48735 Affected pypdf Versions

1 component(s)
Fixed Versions:
6.12.1
Product / Package Ecosystem Affected Versions Fixed Version
pypdf
pypi/pypdf
PyPI
< 6.12.1
6.12.1

References

GitHub Advisory / Wiki ADVISORY
https://github.com/py-pdf/pypdf/security/advisories/GHSA-wjqc-6w8f-h24c
NVD — CVE-2026-48735 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-48735
pypdf Source Repository REPOSITORY
https://github.com/py-pdf/pypdf/pull/3796
pypdf Source Repository REPOSITORY
https://github.com/py-pdf/pypdf
pypdf Release RELEASE
https://github.com/py-pdf/pypdf/releases/tag/6.12.1

Frequently Asked Questions

What is CVE-2026-48735?
CVE-2026-48735 is a security vulnerability in pypdf involving Manipulated XMP metadata streams can exhaust RAM under CWE-770: Allocation of Resources Without Limits or Throttling.
Which pypdf versions are affected?
Affected versions include releases prior to 6.12.1 across affected packages: pypdf.
What version fixes CVE-2026-48735?
Upgrading to 6.12.1 (or the latest patched release for your respective branch) resolves the vulnerability.
Is pypdf affected?
Yes, pypdf is affected in releases prior to 6.12.1. Upgrade your dependency to 6.12.1 or later.
What CWE is associated with CVE-2026-48735?
CVE-2026-48735 is classified under CWE-770: Allocation of Resources Without Limits or Throttling (The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.).
How can I check PyPI dependencies for CVE-2026-48735?
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-wjqc-6w8f-h24c",
  "modified" : "2026-06-16T13:45:58Z",
  "published" : "2026-06-16T13:45:58Z",
  "aliases" : [ "CVE-2026-48735" ],
  "summary" : "pypdf: Manipulated XMP metadata streams can exhaust RAM",
  "details" : "### Impact\n\nAn attacker who uses this vulnerability can craft a PDF which leads to large memory usage. This requires parsing large XMP metadata, possibly with lots of unnecessary elements.\n\n### Patches\nThis has been fixed in [pypdf==6.12.1](https://github.com/py-pdf/pypdf/releases/tag/6.12.1).\n\n### Workarounds\nIf you cannot upgrade yet, consider applying the changes from PR [#3796](https://github.com/py-pdf/pypdf/pull/3796).",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "pypdf"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "6.12.1"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/py-pdf/pypdf/security/advisories/GHSA-wjqc-6w8f-h24c"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-48735"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/py-pdf/pypdf/pull/3796"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/py-pdf/pypdf"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/py-pdf/pypdf/releases/tag/6.12.1"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-770" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-06-16T13:45:58Z",
    "nvd_published_at" : "2026-05-28T16:16:29Z"
  }
}