EspoCRM up to 9.3.3 fromImageUrl dns_get_record server-side request forgery

Summaryinfo

A vulnerability was found in EspoCRM up to 9.3.3. It has been declared as critical. This affects the function dns_get_record of the file /api/v1/Attachment/fromImageUrl. The manipulation results in server-side request forgery. This vulnerability is identified as CVE-2026-33659. The attack can be executed remotely. There is not any exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in EspoCRM up to 9.3.3. It has been classified as critical. Affected is the function dns_get_record of the file /api/v1/Attachment/fromImageUrl. The manipulation with an unknown input leads to a server-side request forgery vulnerability. CWE is classifying the issue as CWE-918. The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-33659 since 03/23/2026. The exploitability is told to be difficult. It is possible to launch the attack remotely. There are known technical details, but no exploit is available.

Upgrading to version 9.3.4 eliminates this vulnerability.

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Productinfo

Name

• EspoCRM

Version

• 9.3.0
• 9.3.1
• 9.3.2
• 9.3.3

License

• open-source

Website

• Product: https://github.com/espocrm/espocrm/

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