What is CVE-2026-31826?

CVE-2026-31826 is a medium-severity vulnerability in Py-Pdf Pypdf, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 5.5/10. Published 2026-03-10.

How severe is CVE-2026-31826?

Medium severity. CVSS v3 base score is 5.5 out of 10.

Resource exhaustion in Py-Pdf Pypdf

CVE-2026-31826

pypdf is a free and open-source pure-python PDF library. Prior to 6.8.0, an attacker who uses this vulnerability can craft a PDF which leads to large memory usage. This requires parsing a content stream with a rather large /Length value, regardless of the actual data length inside the stream. This vulnerability is fixed in 6.8.0.

Published 2026-03-10 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.002 (6.7th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 7th percentile — 6.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: +0.000

Affected products

Py-Pdf Pypdf — versions < 6.8.0
Pypdf Project

Weakness classification (CWE)

CWE-770 — Allocation of Resources Without Limits or Throttling

References

github.com/py-pdf/pypdf/security/advisories/GHSA-hqmh-ppp3-xvm7 (Patch, Vendor Advisory)
github.com/py-pdf/pypdf/pull/3675 (Patch, Issue Tracking)
github.com/py-pdf/pypdf/releases/tag/6.8.0 (Product, Release Notes)

Frequently asked questions

What is CVE-2026-31826?: CVE-2026-31826 is a medium-severity vulnerability in Py-Pdf Pypdf, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 5.5/10. Published 2026-03-10.
How severe is CVE-2026-31826?: Medium severity. CVSS v3 base score is 5.5 out of 10.