CVE-2026-823986.9MediumCWE-407

CVE-2026-82398: pypdf: Inefficient handling of non-whitespace inputs in read_until_whitespace

py-pdf · pypdf

Affected: py-pdf pypdf · Exploitation: unlikely (under 1%)

Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.

0.5%probability of exploitation in the next 30 days

45th percentile

050100

Higher than 45% of scored CVEs

6.9MediumCVSS 4.0

LowMediumHighCrit.

DescriptionCVE.org

pypdf is a free and open-source pure-python PDF library. Prior to 6.15.0, an attacker can craft a PDF that causes long runtimes when the pypdf/_utils.py function read_until_whitespace reads a stream containing a long run of bytes without whitespace. The function repeatedly performs immutable bytes concatenation in a one-byte loop, causing quadratic processing cost for the long non-whitespace input. This issue is fixed in version 6.15.0.

Affected products1

From the CVE record. A product or version that is not listed is unknown, not unaffected.

py-pdf · pypdf< 6.15.0

On the Atlas

Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.

Open the Atlas

Exploitation: Unlikely (under 1%). EPSS under 1%, or no score yet.
CISA KEV: Not listed
Public check: No public nuclei template
Weakness: Inefficient Algorithmic Complexity · Denial of Service
Vendor: py-pdf
Published: August 2026
Band: Unlikely (under 1%), August 2026

CoverageNo articles yet

No CyberSIXT article names CVE-2026-82398 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.