CVE-2021-44168
CVE-2021-44168 is a security flaw in Fortinet FortiOS, the operating system on Fortinet’s FortiGate firewalls. Attackers can read files on Fortinet FortiOS that should be out of reach. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 10 Dec 2021.[1]
Fortinet FortiOS is business software or equipment. Most families won’t have it, but attackers break into it to get inside companies, and from there to what those companies hold about their customers, patients and staff. Fortinet has published a fix or advice.
Description
CISA calls it an arbitrary file download in Fortinet FortiOS. In its words: “Fortinet FortiOS "execute restore src-vis" downloads code without integrity checking, allowing an attacker to arbitrarily download files.”[1]
The CVE record adds: “A download of code without integrity check vulnerability in the "execute restore src-vis" command of FortiOS before 7.0.3 may allow a local authenticated attacker to download arbitrary files on the device via specially crafted update packages.”[2]
The underlying weakness is CWE-494, in MITRE’s list of common software weaknesses.
It scores 7.8 out of 10 on the Common Vulnerability Scoring System, which rates it high, scored by NVD using CVSS 3.1.[2]
Affected versions
NVD’s record doesn’t list version ranges for it; Fortinet’s advisory has them[3]. CISA names the product as Fortinet FortiOS.
Most families won’t have Fortinet FortiOS; it’s for whoever looks after IT at work.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 10 Dec 2021. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 24 Dec 2021 to fix it.[1]
FIRST’s Exploit Prediction Scoring System, which estimates how likely a flaw is to be used in attacks in the next 30 days from what it sees across the internet, puts it at under 1%. That’s in the top 41% of the flaws it scores.[4]
CISA assesses it as not automatable: each attack takes some work.
CISA doesn’t say who was attacked, or how.
Fix
Fortinet has published a fix or advice.[3] CISA’s required action: “Apply updates per vendor instructions.”[1]
- Check whether you use it.Fortinet FortiOS is business software or equipment, so most families won’t have it. If you run a business, or work from home on company equipment, ask whoever looks after your IT.
- Send this page to your IT person.Ask them to confirm it’s fixed, or not in use. CISA gave US government agencies until 24 Dec 2021 to fix it.
- If it can’t be fixed, take it offline.CISA’s advice when there’s no fix is to stop using the product, or take it off the internet, until there is one.
You can’t fix someone else’s server, but you can watch for what follows a break-in like this: a breach notice, a password reset you didn’t ask for, or a scam message that knows things it shouldn’t. HARD watches for those for you and your family.
Timeline
| Date | Event |
|---|---|
| CISA adds it to its catalog of flaws known to be used in attacks.[1] | |
| CISA’s deadline for US government agencies to fix it.[1] | |
| The flaw is made public in the National Vulnerability Database, with a severity score of 7.8.[2] | |
| FIRST puts the odds of it being used in attacks in the next 30 days at under 1%.[4] |
See also
Other Fortinet FortiOS flaws
- CVE-2025-68686: exposure of sensitive information to an unauthorized actor ·
- CVE-2019-6693: use of hard-coded credentials ·
- CVE-2024-21762: out-of-bound write ·
- CVE-2022-41328: path traversal ·
- CVE-2022-42475: heap-based buffer overflow ·
- CVE-2020-12812: SSL VPN improper authentication ·
Other Fortinet flaws
- CVE-2025-61624, Fortinet products: path traversal ·
- CVE-2026-104286, Fortinet FortiMail: path traversal ·
- CVE-2025-25249, Fortinet products: heap-based buffer overflow ·
- CVE-2026-39808, Fortinet FortiSandbox: OS command injection ·
- CVE-2026-25089, Fortinet FortiSandbox: OS command injection ·
Similar flaws
- CVE-2026-3502, TrueConf Client: download of code without integrity check ·
- CVE-2025-15556, Notepad++: download of code without integrity check ·
- CVE-2022-40799, D-Link DNR-322L: download of code without integrity check ·
Added the same day
- CVE-2021-44515, Zoho Desktop Central: authentication bypass ·
- CVE-2021-44228, Apache Log4j2: remote code execution ·
- CVE-2021-35394, Realtek Jungle Software Development Kit (SDK): jungle SDK remote code execution ·
- CVE-2020-8816, Pi-hole AdminLTE: remote code execution ·
- CVE-2020-17463, Fuel CMS: SQL injection ·
Every Fortinet flaw on CISA’s list · Everything added in December 2021
References
- ^ Cybersecurity and Infrastructure Security Agency. “Fortinet FortiOS Arbitrary File Download”. Known Exploited Vulnerabilities Catalog, added 10 Dec 2021.
- ^ National Institute of Standards and Technology. “CVE-2021-44168 Detail”. National Vulnerability Database, published 4 Jan 2022.
- ^ Fortinet. Advisories and fixes: fortiguard.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.009, percentile 59.9, 31 Oct 2026.
- CVE Program. “CVE-2021-44168”. The official CVE record.
This article is built from CISA’s catalog (version 2026.10.30), NVD’s record and FIRST’s scores, kept in HARD’s database and checked every morning. The plain English is HARD’s.