# CVE-2026-4528: trueleaf ApiFlow URL Validation http_proxy.service.ts validateUrlSecurity server-side request forgery

> Remote attackers can exploit a server-side request forgery vulnerability in trueleaf ApiFlow's URL validation to access internal resources.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 21 Mar 2026
- **Updated:** 23 Mar 2026
- **Also known as:** GHSA-29mf-95fh-hwxf

## What is CVE-2026-4528?

CVE-2026-4528 is a medium-severity server-side request forgery vulnerability in trueleaf ApiFlow, published on 21 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability was determined in trueleaf ApiFlow 0.9.7. The impacted element is the function validateUrlSecurity of the file packages/server/src/service/proxy/http_proxy.service.ts of the component URL Validation Handler. This manipulation causes server-side request forgery. Remote exploitation of the attack is possible. The exploit has been publicly disclosed and may be utilized.

Weakness: CWE-918 (Server-Side Request Forgery)

## Which versions are affected by CVE-2026-4528?


## How do I fix CVE-2026-4528?

No fix has been published for CVE-2026-4528 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-4528 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-4528 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-4528 and fix it if it is affected.

What it is: CVE-2026-4528 is a medium-severity server-side request forgery vulnerability in trueleaf ApiFlow, published on 21 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-4528 exists.

Affected product: trueleaf ApiFlow. 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-2026-4528/ (Markdown: https://insights.sbomify.com/CVE-2026-4528/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-4528
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-4528
- OSV: https://osv.dev/vulnerability/CVE-2026-4528

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-4528/
Summaries are generated and may contain mistakes; the official description above is the record.