Bug 2544294 (CVE-2026-102997)

Summary: CVE-2026-102997 pypdf: pypdf: Denial of Service via crafted FlateDecode stream
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: anpicker, bbrownin, blitton, bparees, doconnor, dschmidt, ebourniv, hasun, ikhan, jfula, jlanda, jowilson, kshier, mbarnett, nyancey, ometelka, ptisnovs, rbobbitt, sbunciak, simaishi, stcannon, syedriko, xdharmai, yguenane
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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A flaw was found in pypdf. A remote attacker can exploit this vulnerability by providing a crafted PDF document containing a partially malformed FlateDecode data compression stream. When processing the malformed stream, the application triggers an inefficient recovery routine that consumes excessive processing time, potentially resulting in application unresponsiveness and a Denial of Service (DoS).
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Description OSIDB Bzimport 2026-09-30 20:33:48 UTC
pypdf is a free and open-source pure-python PDF library. Prior to 6.18.1, a crafted PDF containing a partially malformed /FlateDecode stream with padded data can force pypdf/filters.py to use inefficient byte-by-byte decompression while the earlier recovery counter fails to advance for bytes that successfully decode, causing long runtimes and application unavailability. This is a residual issue after the malformed FlateDecode recovery fix. This issue is fixed in version 6.18.1.