CVE-2026-76427 Overview
CVE-2026-76427 is an XML External Entity (XXE) vulnerability in the offline profiler feed service of Cisco Identity Services Engine (ISE). An authenticated remote attacker with administrative credentials can read arbitrary files from the underlying file system and issue requests to internal systems from the affected device. The flaw stems from an XML parser that does not disable external entity resolution when processing attacker-controlled feed metadata. Exploitation requires uploading a crafted offline feed package through the administrative interface.
Critical Impact
Successful exploitation grants arbitrary file read on the Cisco ISE appliance and enables server-side request forgery against internal network resources.
Affected Products
- Cisco Identity Services Engine (ISE)
- Cisco ISE offline profiler feed service
- Refer to the Cisco Security Advisory for specific fixed release information
Discovery Timeline
- 2026-09-16 - CVE-2026-76427 published to NVD
- 2026-09-16 - Last updated in NVD database
Technical Details for CVE-2026-76427
Vulnerability Analysis
The vulnerability is classified under [CWE-611] Improper Restriction of XML External Entity Reference. Cisco ISE processes offline profiler feed packages that include XML metadata describing device profile updates. The XML parser handling this metadata does not disable external entity resolution, allowing DOCTYPE declarations with external entities to be dereferenced during parsing.
An authenticated administrator can craft an offline feed package containing malicious entity definitions. When the appliance parses the feed metadata, it resolves those entities, reading files from the local file system or issuing outbound requests. This provides both arbitrary file disclosure and server-side request forgery (SSRF) capability from the trusted appliance context.
Root Cause
The root cause is an insecurely configured XML parser in the offline profiler feed ingestion pipeline. The parser retains default settings that allow inline DTD processing and external entity resolution. Secure XML parsing requires explicitly disabling DOCTYPE declarations, external general entities, and external parameter entities.
Attack Vector
Exploitation requires valid administrative credentials to the Cisco ISE administrative interface. The attacker authenticates, uploads a crafted offline profiler feed package containing malicious XML metadata, and triggers the feed import workflow. During parsing, defined external entities resolve to local file paths using the file:// scheme or to internal URLs using http:// or https:// schemes. The resulting content is returned in parser output or observable through error messages and out-of-band channels, disclosing arbitrary files and enabling requests to internal-only systems.
No public proof-of-concept code is available. See the Cisco Security Advisory for vendor technical details.
Detection Methods for CVE-2026-76427
Indicators of Compromise
- Unexpected uploads of offline profiler feed packages by administrative accounts, particularly outside normal maintenance windows.
- Outbound DNS or HTTP requests originating from the ISE appliance to attacker-controlled or unusual internal endpoints during or immediately after feed imports.
- Cisco ISE logs referencing XML parsing errors or entity resolution failures during offline feed processing.
Detection Strategies
- Monitor administrative interface audit logs for feed upload events and correlate with the uploading account, source IP, and file provenance.
- Inspect uploaded feed archives for XML files containing <!DOCTYPE> declarations, <!ENTITY> definitions, or references to SYSTEM identifiers.
- Alert on outbound network connections from ISE management interfaces to destinations outside the expected Cisco update infrastructure.
Monitoring Recommendations
- Forward Cisco ISE syslog and administrative audit trails to a central SIEM for correlation of feed operations with network egress activity.
- Baseline expected ISE outbound traffic patterns and generate alerts on deviations, particularly connections to internal RFC1918 endpoints from the appliance.
- Track privileged administrative logins and enforce alerting on new or infrequently used administrator accounts performing feed management operations.
How to Mitigate CVE-2026-76427
Immediate Actions Required
- Restrict access to the Cisco ISE administrative interface to a small set of trusted management hosts using network access control lists.
- Rotate administrative credentials and enforce multi-factor authentication on all Cisco ISE administrator accounts.
- Review recent audit logs for unexpected offline profiler feed uploads and investigate any anomalous entries.
Patch Information
Cisco has published fixed software details in the Cisco Security Advisory cisco-sa-ise-multi-hrP9jQSQ. Administrators should upgrade Cisco ISE to a release listed as fixed by Cisco for this advisory. No official workarounds are provided by the vendor; upgrading is the recommended remediation path.
Workarounds
- Limit administrative account membership to the minimum required personnel and audit role assignments regularly.
- Avoid importing offline profiler feed packages from untrusted or unverified sources until the appliance is patched.
- Segment the Cisco ISE management network from general user networks to reduce exposure of the administrative interface.
Refer to the Cisco Security Advisory for vendor-specific configuration guidance and fixed release information.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
