# CVE-2019-5440: Weak cryptography in Revive Adserver

> Weak random number generation in password recovery tokens allows attackers to predict reset links and take over user accounts.

- **Severity:** High 8.1 (`CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 28 May 2019
- **Updated:** 4 Aug 2024
- **Also known as:** CVE-2019-12396, GHSA-38m3-mrrg-hx5g

## What is CVE-2019-5440?

CVE-2019-5440 is a high-severity vulnerability in Revive-Adserver Revive Adserver, published on 28 May 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Use of cryptographically weak PRNG in the password recovery token generation of Revive Adserver < v4.2.1 causes a potential authentication bypass attack if an attacker exploits the password recovery functionality. In lib/OA/Dal/PasswordRecovery.php, the function generateRecoveryId() generates a password reset token that relies on the PHP uniqid function and consequently depends only on the current server time, which is often visible in an HTTP Date header.

Weakness: CWE-338 (Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG))

## Which versions are affected by CVE-2019-5440?

It affects 1 product.


Products: Revive-Adserver Revive Adserver.

## How do I fix CVE-2019-5440?

No fix has been published for CVE-2019-5440 yet. Limit exposure of the affected software until one is available.

## Is CVE-2019-5440 being exploited?

There is no known exploitation of CVE-2019-5440 in the wild and no public exploit code.

## Other vulnerabilities in Revive-Adserver Revive Adserver

- [CVE-2016-9124](https://insights.sbomify.com/CVE-2016-9124/): Security feature bypass in Revive Adserver All versions before 3.2.3 (critical 9.8)
- [CVE-2016-9125](https://insights.sbomify.com/CVE-2016-9125/): Auth bypass in Revive Adserver All versions before 3.2.3 (critical 9.8)
- [CVE-2017-5830](https://insights.sbomify.com/CVE-2017-5830/): Deserialization in n/a (critical 9.8)
- [CVE-2016-9470](https://insights.sbomify.com/CVE-2016-9470/): Other in Revive Adserver All versions before 3.2.5 and 4.0.0 (critical 9.0)
- [CVE-2026-50741](https://insights.sbomify.com/CVE-2026-50741/): Code injection in Adserver (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-5440 and fix it if it is affected.

What it is: CVE-2019-5440 is a high-severity vulnerability in Revive-Adserver Revive Adserver, published on 28 May 2019. 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-2019-5440 in the wild and no public exploit code.

Affected product: Revive-Adserver Revive Adserver. 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-2019-5440/ (Markdown: https://insights.sbomify.com/CVE-2019-5440/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-5440
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-5440
- OSV: https://osv.dev/vulnerability/CVE-2019-5440

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From sbomify Insights: https://insights.sbomify.com/CVE-2019-5440/
Summaries are generated and may contain mistakes; the official description above is the record.