Buffer overflow in 101arrowz Fflate
CVE-2026-122146
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.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.3 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
- 101arrowz Fflate — versions 0.8.0, 0.8.1, 0.8.2
Weakness classification (CWE)
References
- github.com/ictrun/java/issues/9 (issue-tracking, exploit)
- CVE-2026-122146 | CVE Analysis and Report (third-party-advisory)
- Submit #1027352 | fflate <=0.8.3 Memory Corruption (third-party-advisory)
- VDB-431150 | 101arrowz fflate index.mjs unzipSync memory corruption (technical-description, vdb-entry)
- VDB-431150 | CTI Indicators (IOB, IOC, IOA) (signature, permissions-required)
Frequently asked questions
- What is CVE-2026-122146?
- CVE-2026-122146 is a high-severity vulnerability in 101arrowz Fflate, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 7.3/10. Published 2026-11-05.
- How severe is CVE-2026-122146?
- High severity. CVSS v3 base score is 7.3 out of 10.