# CVE-2026-3963: perfree go-fastdfs-web Apache Shiro RememberMe ShiroConfig.java rememberMeManager hard-coded key

> An attacker can bypass authentication in go-fastdfs-web by exploiting a hard-coded cryptographic key in the Apache Shiro RememberMe configuration.

- **Severity:** Medium 6.3 (`CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 11 Mar 2026
- **Updated:** 12 Mar 2026
- **Also known as:** GHSA-6mp3-5629-4c3x

## What is CVE-2026-3963?

CVE-2026-3963 is a medium-severity vulnerability in perfree go-fastdfs-web, published on 11 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A security flaw has been discovered in perfree go-fastdfs-web up to 1.3.7. This affects the function rememberMeManager of the file src/main/java/com/perfree/config/ShiroConfig.java of the component Apache Shiro RememberMe. Performing a manipulation results in use of hard-coded cryptographic key
 . The attack can be initiated remotely. The complexity of an attack is rather high. The exploitability is reported as difficult. The exploit has been released to the public and may be used for attacks. The vendor was contacted early about this disclosure but did not respond in any way.

Weakness: CWE-321 (Use of Hard-coded Cryptographic Key), CWE-320

## Which versions are affected by CVE-2026-3963?


## How do I fix CVE-2026-3963?

No fix has been published for CVE-2026-3963 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-3963 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-3963 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-3963 and fix it if it is affected.

What it is: CVE-2026-3963 is a medium-severity vulnerability in perfree go-fastdfs-web, published on 11 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-3963 exists.

Affected product: perfree go-fastdfs-web. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-3963/ (Markdown: https://insights.sbomify.com/CVE-2026-3963/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-3963
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-3963
- OSV: https://osv.dev/vulnerability/CVE-2026-3963

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-3963/
Summaries are generated and may contain mistakes; the official description above is the record.