# CVE-2026-27475: SPIP < 4.4.9 Insecure Deserialization

> An attacker with prior access can exploit insecure deserialization in SPIP to achieve arbitrary code execution.

- **Severity:** Critical 9.2 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 19 Feb 2026
- **Updated:** 5 Mar 2026
- **Also known as:** DEBIAN-CVE-2026-27475, GHSA-hxjp-v4qc-fcjg, UBUNTU-CVE-2026-27475

## What is CVE-2026-27475?

CVE-2026-27475 is a critical unsafe deserialization vulnerability in Spip Spip, published on 19 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

SPIP before 4.4.9 allows Insecure Deserialization in the public area through the table_valeur filter and the DATA iterator, which accept serialized data. An attacker who can place malicious serialized content (a pre-condition requiring prior access or another vulnerability) can trigger arbitrary object instantiation and potentially achieve code execution. The use of serialized data in these components has been deprecated and will be removed in SPIP 5. This vulnerability is not mitigated by the SPIP security screen.

Weakness: CWE-502 (Deserialization of Untrusted Data)

## Which versions are affected by CVE-2026-27475?

It affects 1 product.


Products: Spip Spip.

## How do I fix CVE-2026-27475?

Upgrade to a fixed version.

## Is CVE-2026-27475 being exploited?

There is no known exploitation of CVE-2026-27475 in the wild and no public exploit code.

Public exploit code:

- PoC for CVE-2026-27475 (github_poc): https://github.com/Trachinus/CVE-2026-27475

## Other vulnerabilities in Spip Spip

- [CVE-2012-4331](https://insights.sbomify.com/CVE-2012-4331/): Other in n/a (critical 10.0)
- [CVE-2008-5812](https://insights.sbomify.com/CVE-2008-5812/): Other in n/a (critical 10.0)
- [CVE-2024-8517](https://insights.sbomify.com/CVE-2024-8517/): SPIP Bigup Multipart File Upload OS Command Injection (critical 9.8)
- [CVE-2023-24258](https://insights.sbomify.com/CVE-2023-24258/): SQL injection in n/a (critical 9.8)
- [CVE-2017-9736](https://insights.sbomify.com/CVE-2017-9736/): Command injection in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-27475 and fix it if it is affected.

What it is: CVE-2026-27475 is a critical unsafe deserialization vulnerability in Spip Spip, published on 19 Feb 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-2026-27475 in the wild and no public exploit code.

Affected product: Spip Spip. 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-2026-27475/ (Markdown: https://insights.sbomify.com/CVE-2026-27475/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-27475
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-27475
- OSV: https://osv.dev/vulnerability/CVE-2026-27475

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-27475/
Summaries are generated and may contain mistakes; the official description above is the record.