Quick answers
- Is CVE-2026-113791 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-113791 being exploited in the wild.
- How severe is CVE-2026-113791?
- Medium severity, with a CVSS score of 4, published 21 October 2026.
- Which products and versions are affected?
- Pypdf before 6.21.0; pypdf (PyPI) < 6.21.0, ECOSYSTEM:introduced=0,fixed=6.21.0.
- Is there a fix for CVE-2026-113791?
- Yes. pypdf (PyPI): upgrade to 6.21.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-113791 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-113791?
- Check whether you run 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 6.21.0 or later
pip install "pypdf>=6.21.0"
Technical details
A regular expression denial of service (ReDoS) vulnerability exists in pypdf's PDF content stream parsing logic prior to 6.21.0. An attacker can craft a PDF with a content stream containing many small operations that causes the parser to consume large amounts of memory and CPU while processing, even when the stream length itself does not exceed normal limits. The fix introduces configurable parsing limits on stream work, array element counts, and dictionary key-value pair counts.
Affected products
- pypdf pypdf before 6.21.0
Identifiers
- CVE-2026-113791
- GHSA-cgf9-327m-v77c
Timeline
- 2026-10-21: disclosed
- 2026-10-16: patched