CVE-2026-20120: Cisco FTD ACL bypass vulnerability
Tech GuruQuick Answer
CVE-2026-20120 affects vulnerable Cisco ASA and FTD releases with access control lists using Object Group Search (OGS). An unauthenticated remote attacker may send traffic through rules that should block it and reach protected devices. Cisco documents no workaround. Obtain this CVE's First Fixed release for the installed platform and train from Software Checker, not from a combined hardening baseline.
Fix Or Immediate Action
What to do now: Confirm the affected product, release, and configuration. Cisco provides no workaround; reduce exposure where operationally feasible. Enter the exact installed product, platform, and release in Cisco Software Checker and upgrade to the returned First Fixed release. The CVE-specific live advisory and Cisco Software Checker result control the First Fixed release; any combined hardening baseline is supplemental only.
Last verified: 2026-09-17 UTC from Cisco's advisory and CSAF record. Recheck both the affected-products and fixed-software sections before a production change.
Context
Scope And Impact In Plain Language
Who should check: Anyone who manages Cisco Secure Firewall ASA / FTD.
When this applies: Check ASA and FTD appliances running a vulnerable release with access control lists (ACLs) that use Object Group Search (OGS). The product-specific FMC and ASA checks are retained in Affected Scope below; the release and configuration conditions both matter.
What could happen: An unauthenticated remote attacker may send traffic through an affected firewall that its access controls should block, reaching devices in protected networks. This notice describes a traffic-policy bypass, not an established administrative login or code-execution path.
Not sure? Find the exact product, platform, and version in the management interface or CLI, then compare them with this CVE's affected-products section in Cisco's live advisory.
Status At A Glance
| Product scope | Cisco Secure Firewall ASA / FTD |
|---|---|
| CVE | CVE-2026-20120 |
| TechGeeks response tier | P2 — review and schedule |
| Publication | New final Cisco advisory |
| First published | 2026-09-16T16:00:00+00:00 |
| Last updated | 2026-09-16T16:00:00+00:00 |
| Cisco advisory SIR | Medium |
| CVE-specific Cisco SIR | Not separately stated |
| CVSS base score / severity | 5.8 — Medium |
| CVSS vector | CVSS v3.1 — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N |
| CISA KEV at last check | No — this is separate from Cisco severity and is not proof of no exploitation. |
| Cisco exploitation statement | The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerabilities that are described in this advisory. |
What Happened
Cisco describes a logic error when ASA and FTD populate group access control policies with OGS enabled. Traffic that should be blocked can pass through the firewall and reach devices on protected networks. The advisory covers multiple OGS vulnerabilities together; this notice records CVE-2026-20120 and its own score and vector. Cisco has released fixes and lists no workaround. The configuration checks below help identify the OGS prerequisite; release applicability still requires the advisory lookup.
Affected Scope
At the time of publication, these vulnerabilities affected Cisco devices if they were running a vulnerable release of Cisco Secure Firewall ASA Software or Cisco Secure FTD Software and had ACLs with OGS configured. For information about which Cisco software releases are vulnerable, see the Fixed Software section of this advisory. Determine the ACL OGS Configuration on a Device That Is Running Cisco Secure FTD Software To determine whether a device that is running Cisco Secure FTD Software is configured for ACLs with OGS, use the following steps in Cisco Secure Firewall Management Center (FMC) Software: Choose Objects > Object Management. Choose the object type (for example, Network). View the object groups that are listed. If no object groups are listed, the device is not affected by these vulnerabilities. Determine the ACL OGS Configuration on a Device That Is Running Cisco Secure Firewall ASA Software To determine whether a device that is running Cisco Secure Firewall ASA Software is configured for ACPs with OGS, use the CLI command show running-config object-group-search, as shown in the following example: ciscoasa# show running-config object-group-search object-group-search access-control If the output returns no listed object groups, the device is not affected by these vulnerabilities.
Match the exact hardware or virtual platform, installed train, patch level, enabled service, role, and management or data-plane exposure. A Cisco product-family name alone does not establish applicability.
Steps
What To Do Now
- Confirm. Inventory Cisco Secure Firewall ASA / FTD and record platform, exact release, patch level, enabled feature, role, and exposure.
- Preserve. Save UTC context plus off-device authentication, management, firewall, network, endpoint, and SIEM evidence before logs rotate or a disruptive change removes context.
- Scope. Compare each asset with the live Cisco advisory, including configuration prerequisites and exclusions.
- Reduce exposure. Cisco documents no workaround for this CVE. Use only supported exposure controls while preparing the permanent fix.
- Remediate. Follow the CVE-specific method and release guidance under Permanent Fix below.
- Validate. Confirm the resulting version, service health, logging, expected access, an expected denial, failover or cluster state, and representative dependent workflows.
- Escalate. If evidence or exposure creates concern, open incident response and Cisco TAC recovery work rather than treating patch completion as proof of trust.
Fixed Releases And Mitigation
Permanent Fix
Cisco method: Enter the exact ASA/FTD product, platform, and release in Cisco Software Checker. Use this advisory's First Fixed result; a combined hardening recommendation is not a substitute for confirming this CVE.
No compact per-CVE fixed-release table is reproduced here because Cisco may use different First Fixed values by CVE and software train. Use this CVE's live advisory table or Cisco Software Checker; do not infer a fixed release from a combined hardening baseline or another Cisco notice.
Workaround Or Temporary Mitigation
No vendor workaround is documented for CVE-2026-20120. Use supported exposure controls only as temporary risk reduction while preparing the permanent software fix.
Important boundary: A workaround, ACL, exposure reduction, or service restriction can reduce risk while the update is prepared, but it does not patch the vulnerable code, prove every attack path is closed, or erase an earlier compromise.
Investigation And Recovery
Review management authentication, account and privilege changes, API and web requests, configuration changes, crashes or restarts, resource pressure, and relevant external network telemetry for the vulnerable period. Preserve original evidence and follow Cisco TAC or incident-response guidance for containment, credential rotation, trusted rebuild, or service restoration when findings warrant it.
Notes
Exploitation Evidence
Cisco's exact status at the last check: The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerabilities that are described in this advisory.
This CVE was not present in the TechGeeks CISA KEV snapshot at the last check. Cisco's 'not aware' statement and absence from KEV are time-bounded evidence, not claims that exploitation is impossible or has never happened. Severity and exploitation status remain separate signals.
Validation And Boundaries
This notice is documentation-backed. TechGeeks did not reproduce the exploit or independently test every fixed build. It does not prove that all members of the product family are affected, that the activity is widespread, that a clean indicator search excludes compromise, or that an update restored trust. Cisco's live advisory controls affected and fixed release information.
Related TechGeeks Resources
- TechGeeks Security Notice Center
- All Security Notices
- What to Do When a Device Hits CISA KEV
- Router CVE Exposure, Version, and Mitigation Checklist
- IoT Firmware Update and End-of-Support Checklist
- Live Protect and Runtime Vulnerability Shielding
References
Wrap-Up
Record whether CVE-2026-20120 applies. If it does, assign an owner and deadline appropriate to the Medium Cisco advisory SIR, preserve the evidence, complete Cisco's remediation, and document the validated result.
Correction policy: A material Cisco revision to scope, severity, exploitation status, workarounds, fixed software, or recovery guidance triggers an update and a new verification date.
