CVE-2020-3153
CVE-2020-3153 is a security flaw in Cisco AnyConnect Secure, Cisco’s business networking equipment. Attackers are using a flaw in Cisco AnyConnect Secure. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 24 Oct 2022, and says ransomware gangs have used it.[1]
Cisco AnyConnect Secure 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. Fixed in version n/a of Cisco AnyConnect Secure Mobility Client.
Description
CISA calls it a mobility client for windows uncontrolled search path in Cisco AnyConnect Secure. In its words: “Cisco AnyConnect Secure Mobility Client for Windows allows for incorrect handling of directory paths. An attacker with valid credentials on Windows would be able to copy malicious files to arbitrary locations with system level privileges. This could include DLL pre-loading, DLL hijacking, and other related attacks.”[1]
The CVE record adds: “A vulnerability in the installer component of Cisco AnyConnect Secure Mobility Client for Windows could allow an authenticated local attacker to copy user-supplied files to system level directories with system level privileges. The vulnerability is due to the incorrect handling of directory paths. An attacker could exploit this vulnerability by creating a malicious file and copying the file to a system directory. An exploit could allow the attacker to copy malicious files to arbitrary locations with system level privileges. This could include DLL pre-loading, DLL hijacking, and other related attacks. To exploit this vulnerability, the attacker needs valid credentials on the Windows system.”[2]
The underlying weakness is CWE-427, in MITRE’s list of common software weaknesses.
It scores 6.5 out of 10 on the Common Vulnerability Scoring System, which rates it medium, scored by NVD using CVSS 3.1.[2]
Affected versions
NVD’s record lists one fixed version: everything before it is affected.[2]
| Product | Fixed in |
|---|---|
| Cisco AnyConnect Secure Mobility Client | n/a |
Most families won’t have Cisco AnyConnect Secure; it’s for whoever looks after IT at work.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 24 Oct 2022, 978 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 14 Nov 2022 to fix it.[1] CISA says ransomware gangs have used it.
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 29%. That’s in the top 2% 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
Cisco has published a fix or advice.[3] CISA’s required action: “Apply updates per vendor instructions.”[1]
- Check whether you use it.Cisco AnyConnect Secure 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 (fixed in version n/a of Cisco AnyConnect Secure Mobility Client), or not in use. CISA gave US government agencies until 14 Nov 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 6.5.[2] | |
| CISA adds it to its catalog of flaws known to be used in attacks, noting that ransomware gangs have used it.[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 29%.[4] |
See also
Other Cisco AnyConnect Secure flaws
- CVE-2020-3433: mobility client for windows DLL hijacking ·
Other Cisco flaws
- CVE-2026-76418, Cisco Secure Firewall ASA Software and Cisco Secure FTD Software: unchecked return value to NULL pointer dereference ·
- CVE-2026-76519, Cisco Secure Email Gateway: relative path traversal ·
- CVE-2026-76504, Cisco Catalyst SD-WAN Manager: hex encoding ·
- CVE-2026-76460, Cisco Identity Services Engine: incorrect use of privileged APIs ·
- CVE-2026-76461, Cisco Secure Email Gateway: SQL injection ·
Similar flaws
- CVE-2026-110936, Siemens Software Center: uncontrolled search path element ·
Added the same day
- CVE-2020-3433, Cisco AnyConnect Secure: mobility client for windows DLL hijacking ·
- CVE-2018-19323, GIGABYTE products: privilege escalation ·
- CVE-2018-19322, GIGABYTE products: code execution ·
- CVE-2018-19321, GIGABYTE products: privilege escalation ·
- CVE-2018-19320, GIGABYTE products: unspecified ·
Every Cisco flaw on CISA’s list · Everything added in October 2022
References
- ^ Cybersecurity and Infrastructure Security Agency. “Cisco AnyConnect Secure Mobility Client for Windows Uncontrolled Search Path Vulnerability”. Known Exploited Vulnerabilities Catalog, added 24 Oct 2022.
- ^ National Institute of Standards and Technology. “CVE-2020-3153 Detail”. National Vulnerability Database, published 19 Feb 2020.
- ^ Cisco. Advisories and fixes: tools.cisco.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.285, percentile 98.1, 31 Oct 2026.
- CVE Program. “CVE-2020-3153”. 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.