CVE-2026-122146

101arrowz fflate index.mjs unzipSync memory allocation

Published Nov 5, 2026 CVSS 4.0 · 6.9 Medium EPSS < 1% KEV · Not listed
Description
A weakness has been identified in 101arrowz fflate up to 0.8.3. This issue affects the function unzipSync of the file esm/index.mjs. This manipulation causes uncontrolled memory allocation. It is possible to initiate the attack remotely. The exploit has been made available to the public and could be used for attacks. It is suggested to update the configuration settings. The maintainer disputes this issue as a vulnerability. The library is a pure JavaScript decompressor that allocates memory proportional to the decompressed payload size, which is expected behavior. Excessive allocations simply throw a standard JavaScript RangeError or reach engine heap limits. Furthermore, because a low-level decompression library cannot distinguish between a maliciously crafted compression bomb and a legitimate file with a high compression ratio, the API explicitly provides a filter option allowing callers to restrict decompressed file sizes and prevent denial-of-service according to their application's requirements, as seen both in the documentation and noted in the reported issue.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Weaknesses CWE-119
Type Values Removed Values Added
Description A weakness has been identified in 101arrowz fflate up to 0.8.3. This issue affects the function unzipSync of the file esm/index.mjs. This manipulation causes memory corruption. It is possible to initiate the attack remotely. The exploit has been made available to the public and could be used for attacks. The vendor was contacted early about this disclosure but did not respond in any way. A weakness has been identified in 101arrowz fflate up to 0.8.3. This issue affects the function unzipSync of the file esm/index.mjs. This manipulation causes uncontrolled memory allocation. It is possible to initiate the attack remotely. The exploit has been made available to the public and could be used for attacks. It is suggested to update the configuration settings. The maintainer disputes this issue as a vulnerability. The library is a pure JavaScript decompressor that allocates memory proportional to the decompressed payload size, which is expected behavior. Excessive allocations simply throw a standard JavaScript RangeError or reach engine heap limits. Furthermore, because a low-level decompression library cannot distinguish between a maliciously crafted compression bomb and a legitimate file with a high compression ratio, the API explicitly provides a filter option allowing callers to restrict decompressed file sizes and prevent denial-of-service according to their application's requirements, as seen both in the documentation and noted in the reported issue.
Title 101arrowz fflate index.mjs unzipSync memory corruption 101arrowz fflate index.mjs unzipSync memory allocation
Weaknesses CWE-400
CWE-789
References
Metrics cvssV2_0

{'score': 7.5, 'vector': 'AV:N/AC:L/Au:N/C:P/I:P/A:P/E:POC/RL:ND/RC:C'}

cvssV3_0

{'score': 7.3, 'vector': 'CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L/E:P/RL:X/RC:C'}

cvssV3_1

{'score': 7.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L/E:P/RL:X/RC:C'}

cvssV4_0

{'score': 6.9, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P'}

cvssV2_0

{'score': 5, 'vector': 'AV:N/AC:L/Au:N/C:N/I:N/A:P/E:POC/RL:W/RC:C'}

cvssV3_0

{'score': 5.3, 'vector': 'CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:P/RL:W/RC:C'}

cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:P/RL:W/RC:C'}

cvssV4_0

{'score': 6.9, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P'}

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description A weakness has been identified in 101arrowz fflate up to 0.8.3. This issue affects the function unzipSync of the file esm/index.mjs. This manipulation causes memory corruption. It is possible to initiate the attack remotely. The exploit has been made available to the public and could be used for attacks. The vendor was contacted early about this disclosure but did not respond in any way.
Title 101arrowz fflate index.mjs unzipSync memory corruption
First Time appeared 101arrowz
101arrowz fflate
Weaknesses CWE-119
CPEs cpe:2.3:a:101arrowz:fflate:*:*:*:*:*:*:*:*
Vendors & Products 101arrowz
101arrowz fflate
References
Metrics cvssV2_0

{'score': 7.5, 'vector': 'AV:N/AC:L/Au:N/C:P/I:P/A:P/E:POC/RL:ND/RC:C'}

cvssV3_0

{'score': 7.3, 'vector': 'CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L/E:P/RL:X/RC:C'}

cvssV3_1

{'score': 7.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L/E:P/RL:X/RC:C'}

cvssV4_0

{'score': 6.9, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
VulDB
Published
Updated
Nov 10, 2026, 6:07 PM
Reserved
Nov 4, 2026, 6:21 PM
Status
Deferred
Published
Nov 5, 2026, 1:17 AM
Modified
Nov 10, 2026, 7:20 PM