CVE-2026-27888 MEDIUM

CVE-2026-27888: pypdf: Manipulated FlateDecode XFA streams can exhaust RAM

Vendor Py-Pdf
Product pypdf
Weakness CWE-400
Published February 26, 2026
Last update February 26, 2026
View on NVD All CVEs

CVSS base score

6.6/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality —
Integrity —

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U

What the vulnerability does

01Description

pypdf is a free and open-source pure-python PDF library. Prior to 6.7.3, an attacker who uses this vulnerability can craft a PDF which leads to the RAM being exhausted. This requires accessing the `xfa` property of a reader or writer and the corresponding stream being compressed using `/FlateDecode`. This has been fixed in pypdf 6.7.3. As a workaround, apply the patch manually.

Key dates

02Disclosure timeline

February 26, 2026 CVE published
February 26, 2026 Record updated