High severity · published Oct 29, 2026
CVE-2026-119204
pypdf: Possible large memory usage when parsing page tree
New
7.1
CVSS
–
EPSS
No
On KEV
Description
pypdf is a free and open-source pure-python PDF library. Prior to 6.21.4, pypdf can consume excessive memory while parsing a crafted PDF page tree containing many shared resources. Page-tree flattening copies page dictionary and inherited resource entries without a document-wide entry budget, allowing the crafted resource structure to cause disproportionate allocations. This issue is fixed in version 6.21.4.
Exploitation
Is it being used?
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
PY
pypdf · py-pdf
< 6.21.4 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-119204
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-119204
x_refsource_CONFIRM
https://github.com/py-pdf/pypdf/security/advisories/GHSA-cggf-277g-3q54
x_refsource_MISC
https://github.com/py-pdf/pypdf/pull/4290
x_refsource_MISC
https://github.com/py-pdf/pypdf/commit/ea4ac663133f1b3de1d7a8f2e6fa239802fde79e
x_refsource_MISC
https://github.com/py-pdf/pypdf/releases/tag/6.21.4
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