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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2026-33659 Detail

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.


Metrics

 
NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://github.com/espocrm/espocrm/commit/dca03cc3458e487362c26c746378a2d4de9990b1 GitHub, Inc.
https://github.com/espocrm/espocrm/releases/tag/9.3.4 GitHub, Inc.
https://github.com/espocrm/espocrm/security/advisories/GHSA-6m4j-fwrx-crh7 GitHub, Inc.

Weakness Enumeration

CWE-ID CWE Name Source
CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition GitHub, Inc.  
CWE-918 Server-Side Request Forgery (SSRF) GitHub, Inc.  

Change History

1 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-33659
NVD Published Date:
04/13/2026
NVD Last Modified:
04/13/2026
Source:
GitHub, Inc.