Medium severity · published Feb 27, 2026
CVE-2026-28351
Manipulated RunLengthDecode streams can exhaust RAM
5.3
CVSS
0.5%
EPSS
No
On KEV
Description
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 vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
Low
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 41% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
PY
pypdf · py-pdf
< 6.7.4 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-28351
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-28351
Patch
https://github.com/py-pdf/pypdf/commit/f309c6003746414dc7b5048c19e6d879ff2dc858
Issue Tracking
https://github.com/py-pdf/pypdf/pull/3664
Release Notes
https://github.com/py-pdf/pypdf/releases/tag/6.7.4
Patch
https://github.com/py-pdf/pypdf/security/advisories/GHSA-f2v5-7jq9-h8cg
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