# CVE-2026-25863: Conditional Fields for Contact Form 7 < 2.7.3 DoS via Uncontrolled Resource Consumption

> Unauthenticated attackers can cause a denial of service by sending large integers to a REST API endpoint, exhausting server memory in the Conditional Fields for Contact Form 7 plugin.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/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:** No
- **Published:** 4 May 2026
- **Updated:** 25 May 2026
- **Also known as:** GHSA-2g6f-p97f-gp43

## What is CVE-2026-25863?

CVE-2026-25863 is a high-severity denial of service vulnerability in Jules Colle Conditional Fields for Contact Form 7, published on 4 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Conditional Fields for Contact Form 7 WordPress plugin through version 2.7.2 contains an uncontrolled resource consumption vulnerability in the Wpcf7cfMailParser class where the hide_hidden_mail_fields_regex_callback() method reads an iteration count directly from user-supplied POST parameters without validation or upper bound enforcement. Unauthenticated attackers can supply an arbitrarily large integer value through the REST API endpoint to cause unbounded loop execution with multiple preg_replace() operations, exhausting server memory and crashing the PHP process.

Weakness: CWE-1284 (Improper Validation of Specified Quantity in Input)

## Which versions are affected by CVE-2026-25863?


## How do I fix CVE-2026-25863?

No fix has been published for CVE-2026-25863 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-25863 being exploited?

There is no known exploitation of CVE-2026-25863 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-25863 and fix it if it is affected.

What it is: CVE-2026-25863 is a high-severity denial of service vulnerability in Jules Colle Conditional Fields for Contact Form 7, published on 4 May 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-2026-25863 in the wild and no public exploit code.

Affected product: Jules Colle Conditional Fields for Contact Form 7. 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-2026-25863/ (Markdown: https://insights.sbomify.com/CVE-2026-25863/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-25863
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-25863
- OSV: https://osv.dev/vulnerability/CVE-2026-25863

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-25863/
Summaries are generated and may contain mistakes; the official description above is the record.