CVE-2026-40260 pypdf: Manipulated XMP metadata entity declarations can exhaust RAM

What is CVE-2026-40260?

CVE-2026-40260 is a medium-severity denial of service vulnerability in Pypdf Project Pypdf, published on 16 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

pypdf is a free and open-source pure-python PDF library. In versions prior to 6.10.0, manipulated XMP metadata entity declarations can exhaust RAM. An attacker who exploits this vulnerability can craft a PDF which leads to large memory usage. This requires parsing the XMP metadata. This issue has been fixed in version 6.10.0.

Weakness: CWE-776

Which versions are affected by CVE-2026-40260?

3 open source packages ship an affected version, including pypdf. It affects 1 product.

Products include Pypdf Project Pypdf.

How do I fix CVE-2026-40260?

Upgrade pypdf to 6.10.0 or later.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2026-40260 being exploited?

There is no known exploitation of CVE-2026-40260 in the wild and no public exploit code.

Other vulnerabilities in Pypdf Project Pypdf

• CVE-2026-102993 pypdf: Possible large memory usage when retrieving Roman page labels High 8.7
• CVE-2026-102994 pypdf: Possible long runtimes/large memory usage when parsing indirect objects High 8.7
• CVE-2026-102995 pypdf: Possible large memory usage for large /ToUnicode streams (Follow-up 2) High 8.7
• CVE-2026-102996 pypdf: Possible large memory usage when parsing font data High 8.7
• CVE-2026-102997 pypdf: Possible long runtimes for partially malformed FlateDecode streams (Follow-up) High 8.7

All Pypdf Project Pypdf vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2026-40260, ECHO-a89e-cd54-99ff, GHSA-3crg-w4f6-42mx, MINI-rfx2-7jr3-pxc3, MINI-vx82-mp34-7qmq, PYSEC-2026-3006 and 4 more.