Vulnerability Details CVE-2026-45820
fflate through 0.8.2 is vulnerable to denial of service via an infinite loop in unzipSync(). A crafted ZIP archive with a central directory entry declaring compressed_size=0xFFFFFFFF (ZIP64 sentinel) but missing the required ZIP64 extra field tag 0x0001 causes z64e() to loop indefinitely due to out-of-bounds reads returning undefined, which coerces to 0, keeping the loop condition permanently true.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.003
EPSS Ranking 20.5%
CVSS Severity
CVSS v3 Score 7.5
References
Products affected by CVE-2026-45820
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cpe:2.3:a:101arrowz:fflate:0.0.1
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cpe:2.3:a:101arrowz:fflate:0.0.2
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cpe:2.3:a:101arrowz:fflate:0.0.3
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cpe:2.3:a:101arrowz:fflate:0.0.4
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cpe:2.3:a:101arrowz:fflate:0.1.0
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cpe:2.3:a:101arrowz:fflate:0.2.0
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cpe:2.3:a:101arrowz:fflate:0.2.1
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cpe:2.3:a:101arrowz:fflate:0.2.2
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cpe:2.3:a:101arrowz:fflate:0.2.3
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cpe:2.3:a:101arrowz:fflate:0.3.0
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cpe:2.3:a:101arrowz:fflate:0.3.1
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cpe:2.3:a:101arrowz:fflate:0.3.10
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cpe:2.3:a:101arrowz:fflate:0.3.11
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cpe:2.3:a:101arrowz:fflate:0.3.2
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cpe:2.3:a:101arrowz:fflate:0.3.3
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cpe:2.3:a:101arrowz:fflate:0.3.4
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cpe:2.3:a:101arrowz:fflate:0.3.5
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cpe:2.3:a:101arrowz:fflate:0.3.6
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cpe:2.3:a:101arrowz:fflate:0.3.7
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cpe:2.3:a:101arrowz:fflate:0.3.8
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cpe:2.3:a:101arrowz:fflate:0.3.9
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cpe:2.3:a:101arrowz:fflate:0.4.0
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cpe:2.3:a:101arrowz:fflate:0.4.1
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cpe:2.3:a:101arrowz:fflate:0.4.2
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cpe:2.3:a:101arrowz:fflate:0.4.3
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cpe:2.3:a:101arrowz:fflate:0.4.4
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cpe:2.3:a:101arrowz:fflate:0.4.5
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cpe:2.3:a:101arrowz:fflate:0.4.6
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cpe:2.3:a:101arrowz:fflate:0.4.7
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cpe:2.3:a:101arrowz:fflate:0.4.8
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cpe:2.3:a:101arrowz:fflate:0.4.9
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cpe:2.3:a:101arrowz:fflate:0.5.0
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cpe:2.3:a:101arrowz:fflate:0.5.1
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cpe:2.3:a:101arrowz:fflate:0.5.2
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cpe:2.3:a:101arrowz:fflate:0.5.3
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cpe:2.3:a:101arrowz:fflate:0.5.4
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cpe:2.3:a:101arrowz:fflate:0.6.0
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cpe:2.3:a:101arrowz:fflate:0.6.1
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cpe:2.3:a:101arrowz:fflate:0.6.10
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cpe:2.3:a:101arrowz:fflate:0.6.11
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cpe:2.3:a:101arrowz:fflate:0.6.2
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cpe:2.3:a:101arrowz:fflate:0.6.3
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cpe:2.3:a:101arrowz:fflate:0.6.4
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cpe:2.3:a:101arrowz:fflate:0.6.5
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cpe:2.3:a:101arrowz:fflate:0.6.6
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cpe:2.3:a:101arrowz:fflate:0.6.7
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cpe:2.3:a:101arrowz:fflate:0.6.8
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cpe:2.3:a:101arrowz:fflate:0.6.9
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cpe:2.3:a:101arrowz:fflate:0.7.0
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cpe:2.3:a:101arrowz:fflate:0.7.1
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cpe:2.3:a:101arrowz:fflate:0.7.2
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cpe:2.3:a:101arrowz:fflate:0.7.3
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cpe:2.3:a:101arrowz:fflate:0.7.4
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cpe:2.3:a:101arrowz:fflate:0.7.5
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cpe:2.3:a:101arrowz:fflate:0.8.0
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cpe:2.3:a:101arrowz:fflate:0.8.1
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cpe:2.3:a:101arrowz:fflate:0.8.2