# CVE-2026-54806: WordPress WP Activity Log plugin <= 5.6.3.1 - PHP Object Injection vulnerability

> Unauthenticated attackers can exploit PHP object injection in WP Activity Log to potentially execute arbitrary code on the server.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/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:** 17 Jun 2026
- **Updated:** 17 Jun 2026
- **Also known as:** GHSA-5hfr-j85r-7cqx

## What is CVE-2026-54806?

CVE-2026-54806 is a critical unsafe deserialization vulnerability in Melapress WP Activity Log, published on 17 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Unauthenticated PHP Object Injection in WP Activity Log <= 5.6.3.1 versions.

Weakness: CWE-502 (Deserialization of Untrusted Data)

## Which versions are affected by CVE-2026-54806?


## How do I fix CVE-2026-54806?

No fix has been published for CVE-2026-54806 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-54806 being exploited?

There is no known exploitation of CVE-2026-54806 in the wild and no public exploit code.

Public exploit code:

- Unauthenticated PHP Object Injection to RCE in WP Activity Log <= 5.6.3.1 (CVE-2026-54806) (github_poc): https://github.com/joshuavanderpoll/CVE-2026-54806

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-54806 and fix it if it is affected.

What it is: CVE-2026-54806 is a critical unsafe deserialization vulnerability in Melapress WP Activity Log, published on 17 Jun 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-2026-54806 in the wild and no public exploit code.

Affected product: Melapress WP Activity Log. 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-2026-54806/ (Markdown: https://insights.sbomify.com/CVE-2026-54806/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-54806
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-54806
- OSV: https://osv.dev/vulnerability/CVE-2026-54806

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-54806/
Summaries are generated and may contain mistakes; the official description above is the record.