# CVE-2026-8365: Deserialization in Blocksy

> Authenticated contributors can achieve remote code execution via PHP object injection in the Blocksy WordPress theme during database migration.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 9 Jun 2026
- **Updated:** 9 Jun 2026
- **Also known as:** GHSA-r622-c48h-h6qq

## What is CVE-2026-8365?

CVE-2026-8365 is a high-severity unsafe deserialization vulnerability in creativethemeshq Blocksy, published on 9 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

The Blocksy theme for WordPress is vulnerable to PHP Object Injection leading to Remote Code Execution via the 'blocksy_meta' REST API field and the V200 database migration in versions up to and including 2.1.35. This is due to insufficient input sanitization in the blocksy_sanitize_post_meta_options() function, which only blocks values containing '<' or '>' and does not prevent serialized PHP object strings from being stored in post meta, combined with the SearchReplacer::run_recursively() function unconditionally deserializing all string values via @unserialize() during migration without restricting allowed classes. This makes it possible for authenticated attackers, with contributor-level access and above, to inject a serialized Blocksy\RaiiPattern object into post meta that, when the V200 migration runs on an upgraded site, is deserialized and triggers RaiiPattern::__destruct(), which executes arbitrary PHP callables via call_user_func().

Weakness: CWE-502 (Deserialization of Untrusted Data)

## Which versions are affected by CVE-2026-8365?


## How do I fix CVE-2026-8365?

No fix has been published for CVE-2026-8365 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-8365 being exploited?

There is no known exploitation of CVE-2026-8365 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-8365 and fix it if it is affected.

What it is: CVE-2026-8365 is a high-severity unsafe deserialization vulnerability in creativethemeshq Blocksy, published on 9 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-8365 in the wild and no public exploit code.

Affected product: creativethemeshq Blocksy. 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-2026-8365/ (Markdown: https://insights.sbomify.com/CVE-2026-8365/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-8365
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-8365
- OSV: https://osv.dev/vulnerability/CVE-2026-8365

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-8365/
Summaries are generated and may contain mistakes; the official description above is the record.