CVE-2021-26103Network attack vector

Unauthorized SSL-VPN actions via forged requests

Published Dec 8, 2021 · Updated Oct 25, 2024

Cross-site request forgery in FortiOS 7.0.0, 6.4.6 and earlier, and 6.2.9 and earlier allows remote attackers to submit forged SSL-VPN requests. The SSL-VPN portal user interface insufficiently verifies request-data authenticity, but Fortinet has not disclosed the affected endpoint or specific failed check. Exploitation requires user interaction and a portal operating in web or full mode; the resulting unauthorized action has not been publicly specified.

CVSS severity6.3
Medium
EPSS probability0.42%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site request forgery in FortiOS 7.0.0, 6.4.6 and earlier, and 6.2.9 and earlier allows remote attackers to submit forged SSL-VPN requests. The SSL-VPN portal user interface insufficiently verifies request-data authenticity, but Fortinet has not disclosed the affected endpoint or specific failed check. Exploitation requires user interaction and a portal operating in web or full mode; the resulting unauthorized action has not been publicly specified.

The record

CVE
CVE-2021-26103
Published
Dec 8, 2021
Updated
Oct 25, 2024
Vendor
Fortinet
Product
FortiOS
Classifications
CWE-345
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 8, 2021CVE publishedPublication date reported by the CVE source.
  2. Oct 25, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=FortiOS 7.0.0, 6.4.5, 6.4.4, 6.4.3, 6.4.2, 6.4.1, 6.4.0, 6.2.9, 6.2.8, 6.2.7, 6.2.6, 6.2.5, 6.2.4, 6.2.3, 6.2.2, 6.2.1, 6.2.0, 6.0.14, 6.0.13, 6.0.12, 6.0.11, 6.0.10, 6.0.9, 6.0.8, 6.0.7, 6.0.6, 6.0.5, 6.0.4, 6.0.3, 6.0.2, 6.0.1, 6.0.0, 5.6.14, 5.6.13, 5.6.12, 5.6.11, 5.6.10, 5.6.9, 5.6.8, 5.6.7, 5.6.6, 5.6.5, 5.6.4, 5.6.3, 5.6.2, 5.6.1, 5.6.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Fortinet · FortiOSversion=FortiOS 7.0.0, 6.4.5, 6.4.4, 6.4.3, 6.4.2, 6.4.1, 6.4.0, 6.2.9, 6.2.8, 6.2.7, 6.2.6, 6.2.5, 6.2.4, 6.2.3, 6.2.2, 6.2.1, 6.2.0, 6.0.14, 6.0.13, 6.0.12, 6.0.11, 6.0.10, 6.0.9, 6.0.8, 6.0.7, 6.0.6, 6.0.5, 6.0.4, 6.0.3, 6.0.2, 6.0.1, 6.0.0, 5.6.14, 5.6.13, 5.6.12, 5.6.11, 5.6.10, 5.6.9, 5.6.8, 5.6.7, 5.6.6, 5.6.5, 5.6.4, 5.6.3, 5.6.2, 5.6.1, 5.6.0

Published CVSS scores

6.2FortinetCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L/E:F/RL:X/RC:X
5.1NVDAV:N/AC:H/Au:N/C:P/I:P/A:P
6.3FortinetCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L
8.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-345Insufficient Verification of Data Authenticity

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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