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TI-2026-26039 Aliases CVE-2026-33659

EspoCRM: SSRF via DNS Rebinding in Attachment fromImageUrl Endpoint Allows Internal Network Access

Priority MEDIUM 50CWE-367Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
High
Impact type
Information disclosure
Confidentiality · integrity · availability
Low · None · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-918 and the CVSS impact.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00333 26th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed espocrm (espocrm): 9.3.4

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
espocrmespocrmbefore 9.3.49.3.4Patch availableCNA
  • espocrm Vendorespocrm Affected before 9.3.4 Fixed in 9.3.4 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:espocrm:espocrm:*:*:*:*:*:*:*:*before 9.3.4Vulnerableespocrm
  • cpe:2.3:a:espocrm:espocrm:*:*:*:*:*:*:*:* Versions before 9.3.4 Vulnerable ·espocrm

Remediation

  • Fix · CNA espocrm (espocrm) Fixed in 9.3.4

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-33659

References

Exploit 1

Patch 1

Other 1

  • TI-2020-19229 EspoCRM 5.7.0 < 5.9.0 - Two-Factor Authentication Bypass via Auth Token Reuse Between Accounts with Identical Passwords CVSS 4.0HIGH 8.6
  • TI-2026-26036 Path traversal in espocrm CVSS 3.1CRITICAL 9.1
  • TI-2025-32670 EspoCRM vulnerable to LDAP Injection through Improper Neutralization of Special Elements CVSS 3.1MEDIUM 6.5
  • TI-2026-26112 EspoCRM has Admin TemplateManager path traversal that allows arbitrary file read write and delete CVSS 3.1HIGH 7.2
  • TI-2025-23468 EspoCRM vulnerable to HTML Injection into phishing, which may lead to account takeover CVSS 4.0HIGH 7.0
  • TI-2024-16335 EspoCRM weakness in "Forgot password" CVSS 3.1MEDIUM 5.9
See all 39 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences