# CVE-2026-102993: pypdf denial of service via crafted PDF page labels

Source: https://junglewise.ai/threats/cve-2026-102993-pypdf-is-a-free-and-open-source-pure-python-pdf-library-prior-to  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-30. Updated: 2026-09-30  
License: CC BY 4.0 with a link back

CVE-2026-102993 · Severity: high · CVSS 4 · Published 2026-09-30

pypdf is a Python library for reading and manipulating PDF files. A crafted PDF file with unusually large Roman numeral page labels can cause the library to generate excessively large strings, consuming memory and making applications that use pypdf unavailable until they crash or hang. The issue affects versions before 6.17.0 and is fixed in version 6.17.0 and later.

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-2026-102993 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-102993 being exploited in the wild.

**How severe is CVE-2026-102993?** High severity, with a CVSS score of 4, published 30 September 2026.

**Which products and versions are affected?** Py-Pdf Pypdf before 6.17.0; pypdf (PyPI) < 6.17.0, ECOSYSTEM:introduced=0,fixed=6.17.0.

**Is there a fix for CVE-2026-102993?** Yes. pypdf (PyPI): upgrade to 6.17.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-102993 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-102993?** 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 6.17.0 or later

  ```sh
  pip install "pypdf>=6.17.0"
  ```


## Technical details

The vulnerability exists in pypdf/_page_labels.py where Roman numeral conversion does not properly limit the size of generated numerals. An attacker can provide a crafted PDF with abnormally large Roman page-label values, causing the conversion function to generate excessively large numeral strings that consume memory. This is a denial-of-service attack vector accessible via a malicious PDF file, requiring only that an application calls the page label retrieval functionality.

## Affected products

- py-pdf pypdf before 6.17.0

## Identifiers

- CVE-2026-102993
- GHSA-qv6h-rv94-w285
- PYSEC-2026-4158

## Timeline

- 2026-09-30: disclosed
- 2026-09-04: patched: Fix merged in version 6.17.0

## References

- [https://github.com/py-pdf/pypdf/commit/89db7c4fe9315ecc964bfdf05a4e8c4b94175163](https://github.com/py-pdf/pypdf/commit/89db7c4fe9315ecc964bfdf05a4e8c4b94175163)
- [https://github.com/py-pdf/pypdf/pull/4047](https://github.com/py-pdf/pypdf/pull/4047)

## 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 excessive memory consumption in strict mode PDF parsing](https://junglewise.ai/threats/cve-2026-119207-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)