CVE-2025-20281
CVE-2025-20281 is a security flaw in Cisco Identity Services Engine, Cisco’s business networking equipment. Attackers can run their own code on Cisco Identity Services Engine 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 28 Jul 2025.[1]
Cisco Identity Services Engine 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. Cisco has published a fix or advice.
Description
CISA calls it an injection in Cisco Identity Services Engine. In its words: “Cisco Identity Services Engine contains an injection vulnerability in a specific API of Cisco ISE and Cisco ISE-PIC due to insufficient validation of user-supplied input allowing an attacker to exploit this vulnerability by submitting a crafted API request. Successful exploitation could allow an attacker to perform remote code execution and obtaining root privileges on an affected device.”[1]
The CVE record adds: “A vulnerability in a specific API of Cisco ISE and Cisco ISE-PIC could allow an unauthenticated, remote attacker to execute arbitrary code on the underlying operating system as root. The attacker does not require any valid credentials to exploit this vulnerability. This vulnerability is due to insufficient validation of user-supplied input. An attacker could exploit this vulnerability by submitting a crafted API request. A successful exploit could allow the attacker to obtain root privileges on an affected device.”[2]
The underlying weakness is CWE-74, in MITRE’s list of common software weaknesses.
It scores 10.0 out of 10 on the Common Vulnerability Scoring System, which rates it critical, scored by the organisation that published the CVE using CVSS 3.1.[2]
Affected versions
NVD’s record doesn’t list version ranges for it; Cisco’s advisory has them[3]. CISA names the product as Cisco Identity Services Engine.
Most families won’t have Cisco Identity Services Engine; it’s for whoever looks after IT at work.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 28 Jul 2025, 33 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 18 Aug 2025 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 98%. 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
Cisco has published a fix or advice.[3] CISA’s required action: “Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.”[1]
- Check whether you use it.Cisco Identity Services Engine 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 18 Aug 2025 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 10.0.[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 98%.[4] |
See also
Other Cisco Identity Services Engine flaws
- CVE-2026-76460: incorrect use of privileged APIs ·
- CVE-2025-20337: injection ·
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-2026-76461, Cisco Secure Email Gateway: SQL injection ·
- CVE-2026-20079, Cisco Secure Firewall Management Center (FMC) and Security Cloud Control (SCC) Firewall Management: firewall management center authentication bypass using an alternate path or channel ·
Similar flaws
- CVE-2022-43769, Hitachi Vantara Pentaho Business Analytics (BA) Server: pentaho BA server special element injection ·
- CVE-2023-22527, Atlassian Confluence Data Center and Server: template injection ·
- CVE-2022-35914, Teclib GLPI: remote code execution ·
- CVE-2022-46169, Cacti: command injection ·
- CVE-2020-28949, PEAR Archive_Tar: deserialization of untrusted data ·
Added the same day
- CVE-2025-20337, Cisco Identity Services Engine: injection ·
- CVE-2023-2533, PaperCut NG/MF: cross-site request forgery (CSRF) ·
Every Cisco flaw on CISA’s list · Everything added in July 2025
References
- ^ Cybersecurity and Infrastructure Security Agency. “Cisco Identity Services Engine Injection Vulnerability”. Known Exploited Vulnerabilities Catalog, added 28 Jul 2025.
- ^ National Institute of Standards and Technology. “CVE-2025-20281 Detail”. National Vulnerability Database, published 25 Jun 2025.
- ^ Cisco. Advisories and fixes: sec.cloudapps.cisco.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.976, percentile 99.9, 31 Oct 2026.
- CVE Program. “CVE-2025-20281”. 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.