CVE-2021-43063Network attack vector

Browser code execution via crafted login-page requests

Published Dec 8, 2021 · Updated Oct 25, 2024

Cross-site scripting in affected Fortinet FortiWeb 6.2, 6.3, and 6.4 releases allows remote attackers to execute code via login-page GET requests. The login-page request handler places attacker-controlled GET input into generated HTML without adequate neutralization, but Fortinet has not identified the affected parameter or code path. The page is reachable without authentication, but a user must open the crafted request for code to run in that user's browser, limiting the reported impact to confidentiality and integrity.

CVSS severity6.1
Medium
EPSS probability0.89%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in affected Fortinet FortiWeb 6.2, 6.3, and 6.4 releases allows remote attackers to execute code via login-page GET requests. The login-page request handler places attacker-controlled GET input into generated HTML without adequate neutralization, but Fortinet has not identified the affected parameter or code path. The page is reachable without authentication, but a user must open the crafted request for code to run in that user's browser, limiting the reported impact to confidentiality and integrity.

The record

CVE
CVE-2021-43063
Published
Dec 8, 2021
Updated
Oct 25, 2024
Vendor
Fortinet
Product
FortiWeb
Classifications
CWE-79, T1203
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=FortiWeb 6.4.1, 6.4.0, 6.3.15, 6.3.14, 6.3.13, 6.3.12, 6.3.11, 6.3.10, 6.3.9, 6.3.8, 6.3.7, 6.3.6, 6.3.5, 6.3.4, 6.3.3, 6.3.2, 6.3.1, 6.3.0, 6.2.6, 6.2.5, 6.2.4, 6.2.3, 6.2.2, 6.2.1, 6.2.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Fortinet · FortiWebversion=FortiWeb 6.4.1, 6.4.0, 6.3.15, 6.3.14, 6.3.13, 6.3.12, 6.3.11, 6.3.10, 6.3.9, 6.3.8, 6.3.7, 6.3.6, 6.3.5, 6.3.4, 6.3.3, 6.3.2, 6.3.1, 6.3.0, 6.2.6, 6.2.5, 6.2.4, 6.2.3, 6.2.2, 6.2.1, 6.2.0

Published CVSS scores

6.1Fortinet, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:P/A:N
5.8Fortinet, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N/E:P/RL:X/RC:C

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-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

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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