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UK Cyber Defence
VulnerabilityAnalyzed

CVE-2026-84311

Prior to 6.16.1, an attacker can craft a PDF that causes pypdf/_page.py PageObject._extract_text and PageObject.extract_xform_text to traverse a directed acyclic graph of reused form XObjects in which each form invokes a child multiple times, creating…

MEDIUM 4.8EPSS 0.14%

Does this matter?

Lower severity and a low EPSS score (0.14%). Track it; it rarely justifies an emergency change on its own.

Description

pypdf is a free and open-source pure-python PDF library. Prior to 6.16.1, an attacker can craft a PDF that causes pypdf/_page.py PageObject._extract_text and PageObject.extract_xform_text to traverse a directed acyclic graph of reused form XObjects in which each form invokes a child multiple times, creating exponentially many traversal paths and causing long runtimes and large memory consumption. This issue is fixed in version 6.16.1.

CVSS 4.0
4.8 MEDIUMCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
EPSS
0.14% probability · 3th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-834
Affected
pypdf project/pypdf
Source
security-advisories@github.com
EPSS trend
0%3%5%26 October 2026: 0.14%26 October 202626 October 2026

EPSS 0.1% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.