CVE Intelligence
Low Logic error exploit reference

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

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.

Published Apr 13, 2026 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: GitHub_M

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 0.4% (30-day exploitation probability)+5
  • CISA SSVC: exploitation "poc"+5

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
0.4%
ahead of 32% of scored CVEs · Oct 14, 2026
Affects
Espocrm
Espocrm
CVSS base
3.1
Low · 3 source(s)
Prioritization reference: 3.5 provisional

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
Proof of concept
none · proof-of-concept · active
Automatable
No
can an attacker script the kill-chain steps
Technical impact
Partial
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

  • Documented patch — github.com (NIST National Vulnerability Database)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Espocrm Espocrm).
  2. Apply the fixed version or the patch documented under Remediation.
  3. Search available logs for exploit probes matching the vulnerability class (logic error), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Espocrm Espocrm < 9.3.4 Vulnerable NIST National Vulnerability Database
Espocrm Espocrm version < 9.3.4 Vulnerable CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
High
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
None

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
3.5 CVSS 3.1 Low 1.8 1.4 security-advisories@github.com via NIST National Vulnerability Database
3.5 CVSS 3.1 Low — — GitHub_M via CVE Program (cve.org) e CISA ADP
3.1 CVSS 3.1 Low 1.6 1.4 nvd@nist.gov via NIST National Vulnerability Database
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N (score shown at the top: nvd@nist.gov)
Scoring entities (NIST, CNA, ADP) score independently; each score is shown with its origin. For prioritization we use 3.5 (security-advisories@github.com via NIST National Vulnerability Database) as a conservative provisional reference — not a definitive official score.

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-367 · TOCTOU Race Condition

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.40%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
web/proxy/WAF logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first.

  • 2026
  • Affected products added · espocrm/espocrm
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • SSVC assessment updated
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 13, 2026
  • Fix documented
    Oct 13, 2026 · NIST National Vulnerability Database
  • CVSS changed · 3.1
    Oct 13, 2026 · NIST National Vulnerability Database
  • Source status changed · → Analyzed
    Oct 13, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 13, 2026 · NIST National Vulnerability Database
  • CVE published
    Apr 13, 2026 · GitHub_M

Source activity

Repeated readings are counted rather than listed.

  • 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

3 on the record

Elsewhere on this site

Espocrm
every CVE for this vendor
Logic error
same class
CWE-367
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-75505 EspoCRM: Access control bypass in Mass Update letting regular user with Mass Update permission read any attachment 6h
  • CVE-2026-77460 EspoCRM: Mass email template renderer leaks restricted record fields 7h
  • CVE-2026-59994 EspoCRM: Pre-authentication stored HTML injection in stream notification emails about email received 7h
  • CVE-2026-63130 EspoCRM: Admin path traversal in LabelManager (Custom Label saving) allows arbitrary `.json` file read, write and delete 7h
  • CVE-2026-53575 EspoCRM: Persistent XSS via CSP nonce injection in applicationName setting by admin user 7h
  • CVE-2026-53574 EspoCRM: Blind SQL injection via streamAttachments where-clause complex expression 7h

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-33659 is "EspoCRM: SSRF via DNS Rebinding in Attachment fromImageUrl Endpoint Allows Internal Network Access", rated Low. It affects Espocrm (Espocrm); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 3.1 describes technical severity. EPSS 0.40% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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