Pdfly: pypdf: Possible long runtimes when generating appearance streams (CVE-2026-102998)
A vulnerability in pdfly's pypdf library can cause long runtimes when generating appearance streams during form field value updates with flattening enabled. This issue has been fixed in version 6.19.0 of pypdf. Users unable to upgrade immediately can apply changes from a specific pull request as a workaround.
AI Analysis
Technical Summary
CVE-2026-102998 describes a vulnerability in the pdfly product's pypdf library where crafted PDFs can trigger long runtimes by causing appearance stream generation when updating form field values with flattening enabled. This can degrade performance or cause denial of service conditions. The issue affects versions >=0.4.0 and <0.5.1_26. The vulnerability has been addressed in pypdf version 6.19.0.
Potential Impact
An attacker can craft a malicious PDF that, when processed with form field value updates and flattening enabled, causes the application to experience long runtimes. This can lead to denial of service or resource exhaustion conditions. No evidence of exploitation in the wild is known.
Mitigation Recommendations
Upgrade to pypdf version 6.19.0 or later, where this vulnerability is fixed. If immediate upgrade is not possible, apply the changes from pull request #4087 as a temporary workaround.
Pdfly: pypdf: Possible long runtimes when generating appearance streams (CVE-2026-102998)
Description
A vulnerability in pdfly's pypdf library can cause long runtimes when generating appearance streams during form field value updates with flattening enabled. This issue has been fixed in version 6.19.0 of pypdf. Users unable to upgrade immediately can apply changes from a specific pull request as a workaround.
CVSS v4.0
Affected software
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-102998 describes a vulnerability in the pdfly product's pypdf library where crafted PDFs can trigger long runtimes by causing appearance stream generation when updating form field values with flattening enabled. This can degrade performance or cause denial of service conditions. The issue affects versions >=0.4.0 and <0.5.1_26. The vulnerability has been addressed in pypdf version 6.19.0.
Potential Impact
An attacker can craft a malicious PDF that, when processed with form field value updates and flattening enabled, causes the application to experience long runtimes. This can lead to denial of service or resource exhaustion conditions. No evidence of exploitation in the wild is known.
Mitigation Recommendations
Upgrade to pypdf version 6.19.0 or later, where this vulnerability is fixed. If immediate upgrade is not possible, apply the changes from pull request #4087 as a temporary workaround.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- BREW-pdfly-CVE-2026-102998
- Osv Schema Version
- 1.7.3
- Ecosystems
- ["Homebrew"]
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6ac13971a43b0b3b89d5fe15
Added to database: 10/03/2026, 17:20:49 UTC
Last enriched: 10/03/2026, 17:27:17 UTC
Last updated: 10/04/2026, 02:46:02 UTC
Views: 3
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