Medium severity · published Oct 21, 2026
CVE-2026-113791
pypdf: Possible large memory usage when parsing content streams
6.0
CVSS
0.4%
EPSS
No
On KEV
Description
pypdf is a free and open-source pure-python PDF library. Prior to 6.21.0, an attacker can craft a PDF containing a content stream with many small operations, causing parsing to consume large amounts of memory. This issue is fixed in version 6.21.0.
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 33% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
PY
pypdf · py-pdf
< 6.21.0 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-113791
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-113791
github.com
https://github.com/py-pdf/pypdf/commit/18bd2981a74479483a0b9507602c58a63d6c9b12
github.com
https://github.com/py-pdf/pypdf/pull/4218
github.com
https://github.com/py-pdf/pypdf/releases/tag/6.21.0
github.com
https://github.com/py-pdf/pypdf/security/advisories/GHSA-cgf9-327m-v77c
More from pypdf
7.5
CVE-2026-103000
pypdf: Possible large memory usage when retrieving alphabetical page labels
7.5
CVE-2026-102999
pypdf: Possible long runtimes with large amount of embedded files
7.5
CVE-2026-102998
pypdf: Possible long runtimes when generating appearance streams
7.5
CVE-2026-102997
pypdf: Possible long runtimes for partially malformed FlateDecode streams (Follow-up)
7.5
CVE-2026-102996
pypdf: Possible large memory usage when parsing font data