SSRF in Espocrm
CVE-2026-33534
EspoCRM is an open source customer relationship management application. Versions 9.3.3 and below have an authenticated Server-Side Request Forgery (SSRF) vulnerability that allows bypassing the internal-host validation logic by using alternative IPv4 representations such as octal notation (e.g., 0177.0.0.1 instead of 127.0.0.1). This is caused by HostCheck::isNotInternalHost() function relying on PHP's filter_var(..., FILTER_VALIDATE_IP), which does not recognize alternative IP formats, causing the validation to fall through to a DNS lookup that returns no records and incorrectly treats the host as safe, however the cURL subsequently normalizes the address and connects to the loopback destination. Through the confirmed /api/v1/Attachment/fromImageUrl endpoint, an authenticated user can force the server to make requests to loopback-only services and store the fetched response as an attachment. This vulnerability is distinct from CVE-2023-46736 (which involved redirect-based SSRF) and may allow access to internal resources reachable from the application runtime. This issue has been fixed in version 9.3.4.
Vulnerability class: SSRF (Server-Side Request Forgery)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N.
EPSS exploit prediction
EPSS: 0.017 (76.1th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 76th percentile — 76.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.020 · newest: 0.017 · change: -0.003
Affected products
- Espocrm — versions < 9.3.4
Weakness classification (CWE)
Public proof-of-concept exploits
References
- github.com/espocrm/espocrm/security/advisories/GHSA-h7gx-8gwv-7g73 (Exploit, Vendor Advisory)
- github.com/espocrm/espocrm/releases/tag/9.3.4 (Release Notes)
Frequently asked questions
- What is CVE-2026-33534?
- CVE-2026-33534 is a medium-severity vulnerability in Espocrm, classified under Server-Side Request Forgery (SSRF). CVSS score: 4.3/10. Published 2026-04-13.
- How severe is CVE-2026-33534?
- Medium severity. CVSS v3 base score is 4.3 out of 10.
- Is CVE-2026-33534 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.