[KEV] Vulnerability in Cisco Secure Firewall Management Center (FMC) (CVE-2026-20316)
Summary
Vulnerability in Cisco Secure Firewall Management Center (FMC) (CVE-2026-20316). Risk of unauthorized operations or information disclosure. Listed in CISA KEV — actively exploited.
Original description
The description as published by the source.
A vulnerability in the web interface of Cisco Secure Firewall Management Center (FMC) Software could allow an unauthenticated, remote attacker to log in to an affected device using a low-privileged account to access sensitive data within the impacted systems.
This vulnerability is due to the presence of static user credentials for a low-privileged account. An attacker could exploit this vulnerability by using the account to log in to an affected system. A successful exploit could allow the attacker to log in to the affected system and access sensitive data as the low-privileged user.
Note: If the FMC management interface does not have public internet access, the attack surface that is associated with this vulnerability is reduced.
Cisco has assigned this security advisory a Security Impact Rating (SIR) of High rather than Medium as the score indicates. The reason is that this vulnerability can be used with other Cisco Secure FMC Software vulnerabilities to elevate privileges.
Source: Cisco Security Advisories NVD GitHub Advisory CISA KEV
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-20316 has been found in Cisco Secure Firewall Management Center (FMC).
Risk of unauthorized operations or information disclosure. CVSS score: 5.3/10.
Note: CISA has officially confirmed this is actively exploited in the wild. Treat it with elevated urgency.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Cisco Secure Firewall Management Center (FMC) CVE-2026-20316" on the vendor's site.
CVE-2026-20316 (Cisco Secure Firewall Management Center (FMC)) — CWE-259 / CVSS v3 5.3
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Listed in CISA KEV — actively exploited, treat as top priority.
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-259) exists in Cisco Secure Firewall Management Center (FMC).
Check the vendor advisory for the affected versions of Cisco Secure Firewall Management Center (FMC).
Severity: Medium (CVSS 5.3/10). Risk of unauthorized operations or information disclosure. Listed in CISA KEV — actively exploited in the wild, treat as top priority.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Cisco Secure Firewall Management Center (FMC) を使っているサービスとバージョンを洗い出す。
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2Consider incident declaration escalate
Notify SOC / on-callCISA KEV登録済 = 実環境で悪用が観測されている。侵入の兆候があればインシデント対応宣言、無くてもパッチ適用までWAF強化を最優先で。
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3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
References
- advisory NVD
- CISCO sec.cloudapps.cisco.com
- patch psirt@cisco.com
- web github.com
- web cisa.gov