Medium 6.9Published Feb 27, 2026

CVE-2026-28351Manipulated RunLengthDecode streams can exhaust RAM

Updated under an hour ago (Oct 27, 2026, 1:00 AM ET)

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It affects py-pdf pypdf and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for py-pdf pypdf

Exploited in the last 30 days

pypdf is a free and open-source pure-python PDF library. Prior to version 6.7.4, an attacker who uses this vulnerability can craft a PDF which leads to large memory usage. This requires parsing the content stream using the RunLengthDecode filter. This has been fixed in pypdf 6.7.4. As a workaround, consider applying the changes from PR #3664.

CVSS: 6.9 MEDIUM (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Weakness (CWE): CWE-400
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: Analyzed
Record last updated: Mar 3, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

py-pdf pypdf py_pdf:pypdf (from the name)	before 6.7.4	CNA record
pypdf_project pypdf pypdf_project:pypdf	before 6.7.4	NVD

References

References

https://github.com/py-pdf/pypdf/security/advisories/GHSA-f2v5-7jq9-h8cg	x-refsource-confirm, patch, vendor-advisory
https://github.com/py-pdf/pypdf/pull/3664	x-refsource-misc, issue-tracking, patch
https://github.com/py-pdf/pypdf/commit/f309c6003746414dc7b5048c19e6d879ff2dc858	x-refsource-misc, patch
https://github.com/py-pdf/pypdf/releases/tag/6.7.4	x-refsource-misc, release-notes

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.