CVE-2026-45820 | fflate through 0.8.2 is vulnerable to denial of service via … | CVSS 6.6 MEDIUM

Description

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.

Metadata

CVE ID: CVE-2026-45820
State: PUBLISHED
Assigner: seal
Reserved: 2026-05-13 12:03 UTC
Published: 2026-07-22 06:57 UTC
Last updated: 2026-07-22 06:57 UTC
Primary CWE: CWE-835
CWE-835 Loop with Unreachable Exit Condition ('Infinite Loop…
Vendor / Product: 101arrowz / fflate
Sources: cve.org · NVD

Severity & Metrics

6.6 MEDIUM CVSS 4.0

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/S:N/AU:Y/R:U/V:D/RE:M/U:Amber

Affected products (1)

Vendor	Product	Platform	Versions
101arrowz	fflate	Linux,macOS,Windows	0.4.5 ≤ 0.4.8, 0.5.0 ≤ 0.5.3, 0.6.0 ≤ 0.6.10, 0.7.0 ≤ 0.7.4 …

Weakness (CWE)

CWE	Source	Description
CWE-400	cna	CWE-400 Uncontrolled Resource Consumption
CWE-835	cna	CWE-835 Loop with Unreachable Exit Condition ('Infinite Loop')

CVSS scores (1)

Score	Severity	Version	Source	Vector
6.6	MEDIUM	4.0	cna	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/S:N/AU:Y/R:U/V:D/RE:M/U:Amber

References (2)