GitHub Advisoryadvisory · PyPI

GHSA-hqmh-ppp3-xvm7 pypdf: manipulated stream length values can exhaust RAM

MEDIUM Published 2026-03-11 Modified 2026-03-11 Official page ↗
Aliases
CVE-2026-31826
Ecosystem
PyPI
Packages
pypdf
Severity
Moderate
CVSS vector
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Weaknesses
CWE-770
Reviewed
2026-03-11

Affected packages

• PyPI pypdf: < 6.8.0 → fixed in 6.8.0

Description

Impact 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. Patches This has been fixed in pypdf==6.8.0. Workarounds If you cannot upgrade yet, consider applying the changes from PR #3675. As far as we are aware, this mostly affects reading from buffers of unknown size, as returned by `open("file.pdf", mode="rb")` for example. Passing a file path or a `BytesIO` buffer to *pypdf* instead does not seem to trigger the vulnerability.

Related

Alias · CVE (1)

  • CVE-2026-31826 pypdf is a free and open-source pure-python PDF library. vulnerability

Weakness · CWE (1)

  • CWE-770 Allocation of Resources Without Limits or Throttling weakness

References