# CVE-2026-119207: pypdf excessive memory consumption in strict mode PDF parsing

Source: https://junglewise.ai/threats/cve-2026-119207-pypdf-is-a-free-and-open-source-pure-python-pdf-library-prior-to  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-29. Updated: 2026-10-29  
License: CC BY 4.0 with a link back

CVE-2026-119207 · Severity: high · CVSS 4 · Published 2026-10-29

pypdf is a Python library for reading and writing PDF files. When processing a specially crafted invalid PDF in strict mode, the library can consume excessive memory due to error message amplification from nested parsing failures. An attacker could exploit this to cause denial of service by exhausting available memory on systems using pypdf to parse untrusted PDF files.

Technologies: [Py-Pdf Pypdf](https://junglewise.ai/threats/technologies/py-pdf-pypdf), [pypdf (PyPI)](https://junglewise.ai/threats/technologies/pypdf). Vendors: [Py-Pdf](https://junglewise.ai/threats/vendors/py-pdf), [PyPI](https://junglewise.ai/threats/vendors/pypi).

## Quick answers

**Is CVE-2026-119207 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-119207 being exploited in the wild.

**How severe is CVE-2026-119207?** High severity, with a CVSS score of 4, published 29 October 2026.

**Which products and versions are affected?** Py-Pdf Pypdf before 6.21.3; pypdf (PyPI) < 6.21.3, ECOSYSTEM:introduced=0,fixed=6.21.3.

**Is there a fix for CVE-2026-119207?** Yes. pypdf (PyPI): upgrade to 6.21.3 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-119207 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-119207?** Check whether you run Py-Pdf Pypdf or pypdf (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- pypdf (PyPI): upgrade to 6.21.3 or later

  ```sh
  pip install "pypdf>=6.21.3"
  ```


## Technical details

The vulnerability occurs in pypdf's strict mode PDF dictionary parsing, where nested parsing failures cause repeated exception text to accumulate in newly raised error messages. A small malformed dictionary can trigger exponential growth in error message size, exhausting memory. The issue requires loading a crafted invalid PDF and affects versions prior to 6.21.3, where exception chaining now prevents message duplication.

## Affected products

- py-pdf pypdf before 6.21.3

## Identifiers

- CVE-2026-119207
- GHSA-4vqv-7265-gm2w

## Timeline

- 2026-10-29: disclosed
- 2026-10-27: patched

## References

- [https://github.com/py-pdf/pypdf/commit/64270258c0eced720f7960aecf8cef31afd39f8d](https://github.com/py-pdf/pypdf/commit/64270258c0eced720f7960aecf8cef31afd39f8d)
- [https://github.com/py-pdf/pypdf/pull/4265](https://github.com/py-pdf/pypdf/pull/4265)

## Related threats

- [pypdf memory exhaustion in cross-reference stream parsing](https://junglewise.ai/threats/cve-2026-119209-pypdf-is-a-free-and-open-source-pure-python-pdf-library-prior-to)
- [pypdf denial of service via forged encrypted PDF page count](https://junglewise.ai/threats/cve-2026-119208-pypdf-is-a-free-and-open-source-pure-python-pdf-library-prior-to)
- [pypdf denial of service via crafted page labels](https://junglewise.ai/threats/cve-2026-119206-pypdf-is-a-free-and-open-source-pure-python-pdf-library-prior-to)
- [pypdf infinite loop in DictionaryObject cloning](https://junglewise.ai/threats/cve-2026-119205-pypdf-is-a-free-and-open-source-pure-python-pdf-library-prior-to)
- [pypdf excessive memory consumption in PDF page tree parsing](https://junglewise.ai/threats/cve-2026-119204-pypdf-is-a-free-and-open-source-pure-python-pdf-library-prior-to)