# CVE-2026-72545: OpenSignLabs OpenSign - Insecure Direct Object Reference

> Unauthenticated attackers can modify any contact record in OpenSign due to missing authorization checks in the updatecontacttour function.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 11 Aug 2026
- **Updated:** 11 Aug 2026
- **Also known as:** GHSA-4vpg-x7mh-3947

## What is CVE-2026-72545?

CVE-2026-72545 is a high-severity missing authorization vulnerability in OpenSignLabs OpenSign, published on 11 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An insecure direct object reference vulnerability in OpenSignLabs OpenSign through 2.37.0 allows unauthenticated remote attackers to write to any contact record via the updatecontacttour Parse cloud function. The function performs no authentication or authorization before updating the target contact record. An attacker can corrupt or overwrite contact data for any user in the system without credentials.

Weakness: CWE-639 (Authorization Bypass Through User-Controlled Key)

## Which versions are affected by CVE-2026-72545?


## How do I fix CVE-2026-72545?

No fix has been published for CVE-2026-72545 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-72545 being exploited?

There is no known exploitation of CVE-2026-72545 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72545 and fix it if it is affected.

What it is: CVE-2026-72545 is a high-severity missing authorization vulnerability in OpenSignLabs OpenSign, published on 11 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-72545 in the wild and no public exploit code.

Affected product: OpenSignLabs OpenSign. 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-2026-72545/ (Markdown: https://insights.sbomify.com/CVE-2026-72545/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72545
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72545
- OSV: https://osv.dev/vulnerability/CVE-2026-72545

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-72545/
Summaries are generated and may contain mistakes; the official description above is the record.