Pdfly: pypdf: Possible long runtimes for partially malformed FlateDecode streams (Follow-up) (CVE-2026-102997)
A vulnerability in pdfly's pypdf component allows crafted PDF files with partially malformed /FlateDecode streams to cause long runtimes during byte-by-byte decompression. This can lead to denial of service through resource exhaustion. The issue has been fixed in pypdf version 6.18.1. Users unable to upgrade immediately can apply a workaround from the referenced pull request.
AI Analysis
Technical Summary
CVE-2026-102997 describes a vulnerability in pdfly's pypdf library where an attacker can craft a PDF containing a partially malformed /FlateDecode stream. When processed, this causes the decompression routine to operate byte-by-byte, resulting in significantly prolonged runtimes. This behavior can be exploited to degrade service availability. The vulnerability affects versions >=0.4.0 and <0.5.1_26 of pdfly. An official fix is available in pypdf 6.18.1, and a workaround is provided via a specific pull request.
Potential Impact
An attacker can cause long processing times by submitting specially crafted PDF files with malformed /FlateDecode streams. This can lead to denial of service conditions due to resource exhaustion from extended decompression runtimes. There is no indication of code execution or data leakage from the provided information.
Mitigation Recommendations
Upgrade to pypdf version 6.18.1 or later, which contains the official fix for this vulnerability. If immediate upgrade is not possible, apply the changes from pull request #4073 as a temporary workaround.
Pdfly: pypdf: Possible long runtimes for partially malformed FlateDecode streams (Follow-up) (CVE-2026-102997)
Description
A vulnerability in pdfly's pypdf component allows crafted PDF files with partially malformed /FlateDecode streams to cause long runtimes during byte-by-byte decompression. This can lead to denial of service through resource exhaustion. The issue has been fixed in pypdf version 6.18.1. Users unable to upgrade immediately can apply a workaround from the referenced pull request.
CVSS v4.0
Affected software
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-102997 describes a vulnerability in pdfly's pypdf library where an attacker can craft a PDF containing a partially malformed /FlateDecode stream. When processed, this causes the decompression routine to operate byte-by-byte, resulting in significantly prolonged runtimes. This behavior can be exploited to degrade service availability. The vulnerability affects versions >=0.4.0 and <0.5.1_26 of pdfly. An official fix is available in pypdf 6.18.1, and a workaround is provided via a specific pull request.
Potential Impact
An attacker can cause long processing times by submitting specially crafted PDF files with malformed /FlateDecode streams. This can lead to denial of service conditions due to resource exhaustion from extended decompression runtimes. There is no indication of code execution or data leakage from the provided information.
Mitigation Recommendations
Upgrade to pypdf version 6.18.1 or later, which contains the official fix for this vulnerability. If immediate upgrade is not possible, apply the changes from pull request #4073 as a temporary workaround.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- BREW-pdfly-CVE-2026-102997
- Osv Schema Version
- 1.7.3
- Ecosystems
- ["Homebrew"]
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6ac13971a43b0b3b89d5fe16
Added to database: 10/03/2026, 17:20:49 UTC
Last enriched: 10/03/2026, 17:27:26 UTC
Last updated: 10/04/2026, 02:46:02 UTC
Views: 4
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