CVE-2026-102998: CWE-400: Uncontrolled Resource Consumption in py-pdf pypdf
pypdf is a free and open-source pure-python PDF library. Prior to 6.19.0, a crafted PDF with form field values can cause pypdf/generic/_appearance_stream.py appearance-stream generation to repeat invariant selection-data work inside a loop when an application updates fields with flattening enabled, resulting in excessive runtimes and application unavailability. This issue is fixed in version 6.19.0.
AI Analysis
Technical Summary
The pypdf library versions before 6.19.0 contain a vulnerability where a crafted PDF with form field values triggers repeated invariant selection-data work inside a loop in the _appearance_stream.py module during appearance-stream generation. This inefficiency causes uncontrolled resource consumption, resulting in excessive runtimes and potential application unavailability when applications update fields with flattening enabled. The vulnerability is tracked as CWE-400 (Uncontrolled Resource Consumption) and has a CVSS 4.0 score of 8.7, indicating high severity. The issue is resolved in pypdf version 6.19.0.
Potential Impact
Exploitation of this vulnerability can cause denial of service by making the application unresponsive due to excessive runtime resource consumption when processing maliciously crafted PDFs with form fields. There is no indication of privilege escalation, data disclosure, or code execution. The impact is limited to application availability degradation.
Mitigation Recommendations
Upgrade pypdf to version 6.19.0 or later, where this vulnerability is fixed. No other mitigation is required as the fix is officially released.
CVE-2026-102998: CWE-400: Uncontrolled Resource Consumption in py-pdf pypdf
Description
pypdf is a free and open-source pure-python PDF library. Prior to 6.19.0, a crafted PDF with form field values can cause pypdf/generic/_appearance_stream.py appearance-stream generation to repeat invariant selection-data work inside a loop when an application updates fields with flattening enabled, resulting in excessive runtimes and application unavailability. This issue is fixed in version 6.19.0.
CVSS v4.0
Score 8.7high
Affected software
py-pdf
pypdf
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The pypdf library versions before 6.19.0 contain a vulnerability where a crafted PDF with form field values triggers repeated invariant selection-data work inside a loop in the _appearance_stream.py module during appearance-stream generation. This inefficiency causes uncontrolled resource consumption, resulting in excessive runtimes and potential application unavailability when applications update fields with flattening enabled. The vulnerability is tracked as CWE-400 (Uncontrolled Resource Consumption) and has a CVSS 4.0 score of 8.7, indicating high severity. The issue is resolved in pypdf version 6.19.0.
Potential Impact
Exploitation of this vulnerability can cause denial of service by making the application unresponsive due to excessive runtime resource consumption when processing maliciously crafted PDFs with form fields. There is no indication of privilege escalation, data disclosure, or code execution. The impact is limited to application availability degradation.
Mitigation Recommendations
Upgrade pypdf to version 6.19.0 or later, where this vulnerability is fixed. No other mitigation is required as the fix is officially released.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-09-29T20:46:08.335Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6abd72532a4e24523d8ec0e4
Added to database: 09/30/2026, 20:34:27 UTC
Last enriched: 09/30/2026, 20:48:06 UTC
Last updated: 10/01/2026, 04:54:04 UTC
Views: 9
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