CVE-2026-33659

What it is

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.

At a glance

Exploitability

Can be exploited over the network with a low-privilege account. Limited direct impact.

Exploit odds

0.3% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-04-13 21:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 10:37 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.3% in the next 30 days (EPSS).
• Severity: 3.5 LOW (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2026-04-13 21:16 UTC

Last modified

2026-06-17 10:37 UTC

Exploit probability

0.3% · EPSS, next 30 days

Weakness

CWE-367

Record status

Analyzed

Affected

• Espocrm < 9.3.4

Attack profile CVSS 3.1 · 3.5

Attack vector

Network

Complexity

High

Privileges needed

Low

User interaction

None

Scope

Changed

Confidentiality

Low

Integrity

None

Availability

None

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-33659.md and follow it. Check whether this project is affected by CVE-2026-33659. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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