CVE-2026-27888
pypdf: Manipulated FlateDecode XFA streams can exhaust RAM
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.
INFO
Published Date :
Feb. 26, 2026, 1:16 a.m.
Last Modified :
Feb. 27, 2026, 5:26 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Update pypdf to version 6.7.3.
- Apply the manual patch if update is not possible.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-27888.
| URL | Resource |
|---|---|
| https://github.com/py-pdf/pypdf/commit/7a4c8246ed48d9d328fb596942271da47b6d109c | Patch |
| https://github.com/py-pdf/pypdf/pull/3658 | Issue Tracking Patch |
| https://github.com/py-pdf/pypdf/releases/tag/6.7.3 | Product Release Notes |
| https://github.com/py-pdf/pypdf/security/advisories/GHSA-x7hp-r3qg-r3cj | Patch Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-27888 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-27888
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-27888 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-27888 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Feb. 27, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Added CPE Configuration OR *cpe:2.3:a:pypdf_project:pypdf:*:*:*:*:*:*:*:* versions up to (excluding) 6.7.3 Added Reference Type GitHub, Inc.: https://github.com/py-pdf/pypdf/commit/7a4c8246ed48d9d328fb596942271da47b6d109c Types: Patch Added Reference Type GitHub, Inc.: https://github.com/py-pdf/pypdf/pull/3658 Types: Issue Tracking, Patch Added Reference Type GitHub, Inc.: https://github.com/py-pdf/pypdf/releases/tag/6.7.3 Types: Product, Release Notes Added Reference Type GitHub, Inc.: https://github.com/py-pdf/pypdf/security/advisories/GHSA-x7hp-r3qg-r3cj Types: Patch, Vendor Advisory -
New CVE Received by [email protected]
Feb. 26, 2026
Action Type Old Value New Value Added 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. Added CVSS V4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-400 Added Reference https://github.com/py-pdf/pypdf/commit/7a4c8246ed48d9d328fb596942271da47b6d109c Added Reference https://github.com/py-pdf/pypdf/pull/3658 Added Reference https://github.com/py-pdf/pypdf/releases/tag/6.7.3 Added Reference https://github.com/py-pdf/pypdf/security/advisories/GHSA-x7hp-r3qg-r3cj