Log in Start free

Vulnerability · Published Feb 26, 2026 · Assigned by GitHub_M

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

Medium 6.6

In plain English

A medium-severity uncontrolled resource consumption in pypdf from py-pdf. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 34% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)6.6Medium
Exploit odds (30 days)0.4%top 65.7% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12pypdfno fix listedDEBIAN-CVE-2026-27888
Debian:13pypdfno fix listedDEBIAN-CVE-2026-27888
Debian:14pypdf6.9.0-1DEBIAN-CVE-2026-27888
Debian:12pypdf2no fix listedDEBIAN-CVE-2026-27888
PyPIpypdf6.7.3GHSA-x7hp-r3qg-r3cj
PyPIpypdf6.7.3PYSEC-2026-3027
Ubuntu:24.04:LTSpypdfno fix listedUBUNTU-CVE-2026-27888
Ubuntu:25.10pypdfno fix listedUBUNTU-CVE-2026-27888
Ubuntu:26.04:LTSpypdfno fix listedUBUNTU-CVE-2026-27888
Ubuntu:26.10pypdfno fix listedUBUNTU-CVE-2026-27888

Affected products (as reported)

VendorProductVersions
py-pdf pypdf < 6.7.3

Weakness: CWE-400 · 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

References