CVE-2026-33534

MEDIUMNVD 4.34.3—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 4.3 under NVD CVSS v3. EPSS exploit probability: 2.0%, top 21% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
Elevated
4.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 2%CVSS: 4.3Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
4.3
EG Score
4.3(medium)
EG Risk
35(Track)
EG Risk 35/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity43% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
2%
EPSS %ILE
79%
KEV
Not listed

Published

April 13, 2026

Last Modified

April 22, 2026

Advisory Details (2)

Auto-updated Aug 5, 2026
🔬 Proof of concept available. Patch available. Sources: github_release, github.
github Patch Available🟡 PoC Available

Authenticated SSRF via internal-host validation bypass using alternative IPv4 notation · Advisory · espocrm/espocrm · GitHub

https://github.com/espocrm/espocrm/security/advisories/GHSA-h7gx-8gwv-7g73
github_release Patch Available

Release 9.3.4 (espocrm/espocrm)

Patch available: espocrm/espocrm 9.3.4

https://github.com/espocrm/espocrm/releases/tag/9.3.4

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 6× in last 7d / 30× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 159 total refreshes for this CVE.

  1. 2026-09-15 03:11 UTCEPSS rescore
  2. 2026-09-12 15:01 UTCEPSS rescore
  3. 2026-09-11 14:53 UTCEPSS rescore
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  12. 2026-09-02 05:28 UTCOSV refresh
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  6. 2026-08-16 06:53 UTCEG score recompute
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  22. 2026-08-05 19:17 UTCEPSS rescore
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  25. 2026-08-03 21:48 UTCEG score recompute
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  41. 2026-07-23 03:09 UTCEG score recompute
  42. 2026-07-22 14:08 UTCEPSS rescore
  43. 2026-07-21 15:24 UTCEPSS rescore
  44. 2026-07-20 17:08 UTCEPSS rescore
  45. 2026-07-20 11:04 UTCOSV refresh
  46. 2026-07-19 14:31 UTCEPSS rescore
  47. 2026-07-19 02:29 UTCEPSS rescore
  48. 2026-07-18 10:04 UTCEPSS rescore
  49. 2026-07-16 17:03 UTCEPSS rescore
  50. 2026-07-15 16:57 UTCEPSS rescore
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  74. 2026-06-27 03:08 UTCEPSS rescore
  75. 2026-06-25 13:49 UTCEPSS rescore

Publicly available exploits

(2 references)

Working exploit code is in the public domain (1 Exploit-DB entry). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • Exploit-DBEDB-52583
    First seen May 27, 2026

    EspoCRM 9.3.3 - SSRF

    Open source ↗
  • Nucleihttp/cves/2026/CVE-2026-33534.yaml
    First seen Jan 1, 2026

    EspoCRM <= 9.3.3 - Server-Side Request Forgery

    Open source ↗

Frequently asked(5)

What is CVE-2026-33534?
CVE-2026-33534 is a medium vulnerability published on April 13, 2026. 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.,…
When was CVE-2026-33534 disclosed?
CVE-2026-33534 was first published in the National Vulnerability Database on April 13, 2026, with the most recent update on April 22, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-33534 actively exploited?
CVE-2026-33534 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 2% probability of exploitation in the next 30 days, which ranks it in the top 20.6% of all scored CVEs.
What is the CVSS score of CVE-2026-33534?
CVE-2026-33534 has a CVSS v3 base score of 4.3 (NVD).
How do I remediate CVE-2026-33534?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-33534, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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