# CVE-2026-112040: diem-project diem Sign-In BasedmUserActions.class.php redirect

> An open redirect vulnerability in the diem Sign-In component allows attackers to redirect users to malicious sites via the Referer argument.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/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:** A user has to click or open something
- **Fix available:** No
- **Published:** 19 Oct 2026
- **Updated:** 19 Oct 2026
- **Also known as:** GHSA-2fp3-3pqm-j39r

## What is CVE-2026-112040?

CVE-2026-112040 is a medium-severity vulnerability in diem-project diem, published on 19 Oct 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

A vulnerability was determined in diem-project diem up to 116974edfb9a5b8bd69cb13586dc62bcdbb485ad. This affects an unknown part of the file dmCorePlugin/plugins/dmUserPlugin/modules/dmUser/lib/BasedmUserActions.class.php of the component Sign-In. This manipulation of the argument Referer causes open redirect. The attack is possible to be carried out remotely. The exploit has been publicly disclosed and may be utilized. This product adopts a rolling release strategy to maintain continuous delivery. Therefore, version details for affected or updated releases cannot be specified. The project was informed of the problem early through an issue report but has not responded yet.

Weakness: CWE-601 (URL Redirection to Untrusted Site)

## Which versions are affected by CVE-2026-112040?


## How do I fix CVE-2026-112040?

No fix has been published for CVE-2026-112040 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-112040 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-112040 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-112040 and fix it if it is affected.

What it is: CVE-2026-112040 is a medium-severity vulnerability in diem-project diem, published on 19 Oct 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-112040 exists.

Affected product: diem-project diem. 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-2026-112040/ (Markdown: https://insights.sbomify.com/CVE-2026-112040/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-112040
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-112040
- OSV: https://osv.dev/vulnerability/CVE-2026-112040

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-112040/
Summaries are generated and may contain mistakes; the official description above is the record.