CVE Intelligence
High Memory corruption

CVE-2026-70465 — Classic Buffer Overflow in Fortinet FortiClientWindows

A buffer copy without checking size of input ('classic buffer overflow') vulnerability in Fortinet FortiClientWindows 7.4.0 through 7.4.3, FortiClientWindows 7.2.0 through 7.2.11 may allow an unauthenticated attacker in a position to alter or craft DNS responses to the targeted host to execute arbitrary code via malicious packets.

Published Aug 12, 2026 · Updated Oct 15, 2026 · Sources: CVE Program (cve.org) e CISA ADP · CNA: fortinet

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
  • Technical severity (high)+6

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
—
No EPSS score.
Affects
Fortinet
FortiClientWindows
CVSS base
7.3
High · 1 source(s)

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

Remediation

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

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

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 (Fortinet FortiClientWindows).
  2. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
  3. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  4. Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Fortinet FortiClientWindows ≥ 7.4.0 and ≤ 7.4.3≥ 7.2.0 and ≤ 7.2.11 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
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Every base score collected

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

ScoreVersionSeverityExpl.ImpactScored by
7.3 CVSS 3.1 High — — fortinet via CVE Program (cve.org) e CISA ADP
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C (score shown at the top: fortinet)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-120 · Classic Buffer Overflow

Other CVEs with this weakness →

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).
  • Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.
web/proxy/WAF logsnetwork IDS/IPSendpoint telemetry (EDR)crash dumps

Timeline

What happened to this CVE, newest first.

  • 2026
  • Record published
    Oct 15, 2026
  • CVSS changed · 7.3
    Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
  • Source status changed · → Published
    Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
  • SSVC assessment updated
    Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
  • Record created in this database
    Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
  • CVE published
    Aug 12, 2026 · fortinet

Source activity

Repeated readings are counted rather than listed.

  • 1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

1 on the record

Elsewhere on this site

Fortinet
every CVE for this vendor
Memory corruption
same class
CWE-120
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-44278 A use of hard-coded cryptographic key vulnerability in Fortinet FortiClientWindows 7.4.0… May 12, 2026
  • CVE-2025-62676 Link Following in Fortinet Forticlient Feb 10, 2026
  • CVE-2025-54660 An active debug code vulnerability in Fortinet FortiClientWindows 7.4.0 through 7.4.3… Nov 18, 2025
  • CVE-2025-47761 An Exposed IOCTL with Insufficient Access Control vulnerability [CWE-782] vulnerability… Nov 18, 2025
  • CVE-2025-46373 Heap-based Buffer Overflow in Fortinet Forticlient Nov 18, 2025
  • CVE-2025-57716 Uncontrolled Search Path Element in Fortinet Forticlient Oct 14, 2025

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 FIRST EPSS score.
  • No fixed version, patch or mitigation documented.
  • 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-2026-70465 is "Classic Buffer Overflow in Fortinet FortiClientWindows", rated High. It affects FortiClientWindows (Fortinet); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.3 describes technical severity. 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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