High 7.1Published Oct 29, 2026

CVE-2026-119209pypdf: Possible large memory usage when parsing cross-reference streams

Updated under an hour ago (Oct 30, 2026, 4:40 AM ET)

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No exploitation reported and no EPSS estimate yet.

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pypdf is a free and open-source pure-python PDF library. Prior to 6.21.3, pypdf can consume excessive memory while opening a crafted PDF containing cross-reference streams that declare very large entry counts. Highly compressible streams and /Prev chains can multiply the number of parsed entries across a document, while negative /Index counts can bypass the existing per-stream clamp. This issue is fixed in version 6.21.3.

CVSS: 7.1 HIGH (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Weakness (CWE): CWE-400, CWE-770
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Received
Record last updated: Oct 29, 2026
First seen by InfoSec Signals: Oct 29, 2026

Affected products

Affected products

py-pdf pypdf py_pdf:pypdf (from the name)	before 6.21.3	CNA record

References

References

https://github.com/py-pdf/pypdf/security/advisories/GHSA-x3rh-gjgm-fmqc	x-refsource-confirm
https://github.com/py-pdf/pypdf/pull/4269	x-refsource-misc
https://github.com/py-pdf/pypdf/commit/a93fe3a901fd00af38f0a105c3ba7175fa72dcb4	x-refsource-misc
https://github.com/py-pdf/pypdf/releases/tag/6.21.3	x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.