CVE-2026-122146 101arrowz fflate index.mjs unzipSync memory allocation
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2026-122146?
CVE-2026-122146 is a medium-severity vulnerability in 101arrowz fflate, published on 5 Nov 2026.
Official 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.
Which versions are affected by CVE-2026-122146?
How do I fix CVE-2026-122146?
No fix has been published for CVE-2026-122146 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-122146 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-122146 exists.
Sources
Also known as GHSA-3xf2-c6c2-98qc.