CVE-2021-40870
CVE-2021-40870 is a security flaw in Aviatrix Controller. Attackers can run their own code on Aviatrix Controller from anywhere, without logging in. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 18 Jan 2022.[1]
Aviatrix Controller 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. Aviatrix has published a fix or advice.
Description
CISA calls it a controller unrestricted upload of file in Aviatrix Aviatrix Controller. In its words: “Unrestricted upload of a file with a dangerous type is possible, which allows an unauthenticated user to execute arbitrary code via directory traversal.”[1]
The CVE record adds: “An issue was discovered in Aviatrix Controller 6.x before 6.5-1804.1922. Unrestricted upload of a file with a dangerous type is possible, which allows an unauthenticated user to execute arbitrary code via directory traversal.”[2]
The underlying weakness is CWE-25, CWE-96, in MITRE’s list of common software weaknesses.
It scores 9.8 out of 10 on the Common Vulnerability Scoring System, which rates it critical, scored by NVD using CVSS 3.1.[2]
Affected versions
NVD’s record doesn’t list version ranges for it; Aviatrix’s advisory has them[3]. CISA names the product as Aviatrix Aviatrix Controller.
Most families won’t have Aviatrix Controller; it’s for whoever looks after IT at work.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 18 Jan 2022, 127 days after it was made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 1 Feb 2022 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 93%. That’s in the top 1% of the flaws it scores.[4]
CISA assesses it as automatable: attackers can run it against many targets at once.
CISA doesn’t say who was attacked, or how.
Fix
Aviatrix has published a fix or advice.[3] CISA’s required action: “Apply updates per vendor instructions.”[1]
- Check whether you use it.Aviatrix Controller 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 1 Feb 2022 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 |
|---|---|
| The flaw is made public in the National Vulnerability Database, with a severity score of 9.8.[2] | |
| 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] | |
| FIRST puts the odds of it being used in attacks in the next 30 days at 93%.[4] |
See also
Other Aviatrix flaws
- CVE-2024-50603, Aviatrix Controllers: OS command injection ·
Similar flaws
- CVE-2022-20775, Cisco SD-WAN: path traversal ·
Added the same day
- CVE-2021-33766, Microsoft Exchange Server: information disclosure ·
- CVE-2021-32648, October CMS: improper authentication ·
- CVE-2021-25298, Nagios XI: XI OS command injection ·
- CVE-2021-25297, Nagios XI: XI OS command injection ·
- CVE-2021-25296, Nagios XI: XI OS command injection ·
References
- ^ Cybersecurity and Infrastructure Security Agency. “Aviatrix Controller Unrestricted Upload of File”. Known Exploited Vulnerabilities Catalog, added 18 Jan 2022.
- ^ National Institute of Standards and Technology. “CVE-2021-40870 Detail”. National Vulnerability Database, published 13 Sep 2021.
- ^ Aviatrix. Advisories and fixes: docs.aviatrix.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.930, percentile 99.8, 31 Oct 2026.
- CVE Program. “CVE-2021-40870”. 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.