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.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/101arrowz/fflate/blob/f7873560ad229c22c4b23b06c6a3806ffde77569/src/index.ts#L2714	Patch
https://www.npmjs.com/package/fflate	Product

Configurations

Configuration 1 (hide)

cpe:2.3:a:101arrowz:fflate:*:*:*:*:*:node.js:*:*

History

No history.

Information

Published : 2026-07-22 08:16

Updated : 2026-08-19 19:06

NVD link : CVE-2026-45820

Mitre link : CVE-2026-45820

CVE.ORG link : CVE-2026-45820

JSON object : View

Products Affected

101arrowz

fflate

CWE

CWE-400

Uncontrolled Resource Consumption

CWE-835

Loop with Unreachable Exit Condition ('Infinite Loop')

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