CVE-2020-29016Network attack vector

Arbitrary code execution via oversized certname parameter

Published Jan 14, 2021 · Updated Oct 25, 2024

Stack-based buffer overflow in Fortinet FortiWeb 6.2.4 and earlier and 6.3.0 through 6.3.9 allows remote attackers to execute arbitrary code. Processing a crafted HTTP request with an oversized certname parameter overwrites a stack buffer; Fortinet has not identified the affected function. No authentication or user interaction is required, and successful exploitation executes code in the appliance context.

CVSS severity9.8
Critical
EPSS probability3.30%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack-based buffer overflow in Fortinet FortiWeb 6.2.4 and earlier and 6.3.0 through 6.3.9 allows remote attackers to execute arbitrary code. Processing a crafted HTTP request with an oversized certname parameter overwrites a stack buffer; Fortinet has not identified the affected function. No authentication or user interaction is required, and successful exploitation executes code in the appliance context.

The record

CVE
CVE-2020-29016
Published
Jan 14, 2021
Updated
Oct 25, 2024
Vendor
Fortinet
Product
FortiWeb
Classifications
CWE-787, CWE-121, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 14, 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

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=FortiWeb 6.3.0 through 6.3.5 and version before 6.2.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Fortinet · FortiWebversion=FortiWeb 6.3.0 through 6.3.5 and version before 6.2.4

Published CVSS scores

7.5NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/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-787Out-of-bounds Write
CWE-121Stack-based Buffer Overflow
T1190Exploit Public-Facing Application

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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