# CVE-2026-33659: EspoCRM: SSRF via DNS Rebinding in Attachment fromImageUrl Endpoint Allows Internal Network Access

> Authenticated attackers can exploit DNS rebinding in EspoCRM to bypass IP restrictions and access internal network services.

- **Severity:** Low 3.5 (`CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N`)
- **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:** 13 Apr 2026
- **Updated:** 14 Apr 2026
- **Also known as:** GHSA-6m4j-fwrx-crh7

## What is CVE-2026-33659?

CVE-2026-33659 is a low-severity server-side request forgery vulnerability in espocrm, published on 13 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

EspoCRM is an open source customer relationship management application. In versions 9.3.3 and below, the POST /api/v1/Attachment/fromImageUrl endpoint is vulnerable to Server-Side Request Forgery (SSRF) via a DNS rebinding (TOCTOU) condition. Host validation uses dns_get_record() but the actual HTTP request resolves hostnames through curl's internal resolver (gethostbyname()), allowing the two lookups to return different IP addresses for the same hostname. A secondary issue exists where an empty DNS result (due to DNS failure, IPv6-only domains, or non-existent hostnames) causes the validation to implicitly allow the host without further checks. An authenticated attacker with default attachment creation access can exploit this gap to bypass internal IP restrictions and scan internal network ports, confirm the existence of internal hosts, and interact with internal HTTP-based services, though data extraction from binary protocol services and remote code execution are not possible through this endpoint. This issue has been fixed in version 9.3.4.

Weakness: CWE-918 (Server-Side Request Forgery), CWE-367 (Time-of-check Time-of-use (TOCTOU) Race Condition)

## Which versions are affected by CVE-2026-33659?

It affects 1 product.


Products: Espocrm Espocrm.

## How do I fix CVE-2026-33659?

No fix has been published for CVE-2026-33659 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-33659 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-33659 exists.

## Other vulnerabilities in espocrm

- [CVE-2014-7985](https://insights.sbomify.com/CVE-2014-7985/): Path traversal in n/a (critical 10.0)
- [CVE-2026-33656](https://insights.sbomify.com/CVE-2026-33656/): Path traversal in espocrm (critical 9.1)
- [CVE-2022-38843](https://insights.sbomify.com/CVE-2022-38843/): File upload in n/a (high 8.8)
- [CVE-2019-14351](https://insights.sbomify.com/CVE-2019-14351/): Information disclosure in n/a (high 8.8)
- [CVE-2020-37094](https://insights.sbomify.com/CVE-2020-37094/): EspoCRM 5.7.0 < 5.9.0 - Two-Factor Authentication Bypass via Auth Token Reuse Between Accounts with Identical Passwords (high 8.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-33659 and fix it if it is affected.

What it is: CVE-2026-33659 is a low-severity server-side request forgery vulnerability in espocrm, published on 13 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-33659 exists.

Affected product: espocrm. 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-2026-33659/ (Markdown: https://insights.sbomify.com/CVE-2026-33659/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-33659
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-33659
- OSV: https://osv.dev/vulnerability/CVE-2026-33659

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-33659/
Summaries are generated and may contain mistakes; the official description above is the record.