Denial of Service (DoS) Affecting pypdf package, versions [,6.21.2)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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- published23 Oct 2026
- disclosed23 Oct 2026
- creditmanop55555
Introduced: 23 Oct 2026
NewCVE-2026-115572 (opens in a new tab)How to fix?
Upgrade pypdf to version 6.21.2 or higher.
Overview
pypdf is an A pure-python PDF library capable of splitting, merging, cropping, and transforming PDF files
Affected versions of this package are vulnerable to Denial of Service (DoS) via repeated full file loads triggered by malformed PDF input. When get_object in pypdf/_reader.py encounters an invalid or unresolvable indirect object reference, it falls back to a full sequential scan of the underlying stream on every access attempt, rather than caching the result. Similarly, _read_standard_xref_table re-reads the entire file buffer each time a cross-reference entry fails to parse during recovery. An attacker can supply a PDF containing many such invalid objects or a corrupt cross-reference table, causing the parser to repeatedly read the full file into memory and exhausting available resources.
Details
Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its intended and legitimate users.
Unlike other vulnerabilities, DoS attacks usually do not aim at breaching security. Rather, they are focused on making websites and services unavailable to genuine users resulting in downtime.
One popular Denial of Service vulnerability is DDoS (a Distributed Denial of Service), an attack that attempts to clog network pipes to the system by generating a large volume of traffic from many machines.
When it comes to open source libraries, DoS vulnerabilities allow attackers to trigger such a crash or crippling of the service by using a flaw either in the application code or from the use of open source libraries.
Two common types of DoS vulnerabilities:
High CPU/Memory Consumption- An attacker sending crafted requests that could cause the system to take a disproportionate amount of time to process. For example, commons-fileupload:commons-fileupload.
Crash - An attacker sending crafted requests that could cause the system to crash. For Example, npm
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