CVE-2026-76483

Executive Summary

CVE-2026-76483 is an aggregate identifier assigned by Cisco to a set of internally discovered vulnerabilities in Cisco License On-Prem (formerly Cisco Smart Software Manager On-Prem) that share the root cause class CWE-522, Insufficiently Protected Credentials. The flaw carries a CVSS v3.1 base score of 9.1 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N), meaning an unauthenticated remote attacker can achieve high confidentiality and integrity impact against affected deployments. Cisco License On-Prem is a license management and entitlement platform commonly positioned internally yet reachable from enterprise networks, making it a high-value target for credential theft and downstream license/account compromise.

Technical Analysis

CWE-522 is a CWE Pillar that groups weaknesses involving the storage, transmission, or handling of credentials in a manner that does not adequately protect them. Cisco's advisory describes the underlying issue only at this pillar level: the vulnerabilities were found during an internal security review and are grouped as "issues with insufficiently protected credentials." No specific child weakness (for example, cleartext transmission, plaintext storage, or weak hashing) was disclosed, and no affected code components, files, or interfaces were named in the source data.

From the CVSS vector, several properties are directly inferable and should be treated as authoritative:

• AV:N — the attack is network-deliverable; the vulnerable interface is reachable over the network rather than requiring local or adjacent access.
• AC:L — no unusual preconditions or race conditions are required.
• PR:N — no authentication is needed prior to abuse.
• UI:N — no user interaction is required.
• S:U — impact is scoped to the vulnerable component.
• C:H / I:H / A:N — high confidentiality and integrity impact, no availability impact.

The combination of PR:N, AV:N, and C:H/I:H is consistent with an exposure in which credential material (for example, service account secrets, license/entitlement tokens, or administrative credentials) can be obtained or manipulated by an unauthenticated remote party. Because the affected product is a license management platform, exposure of its stored credentials is not a self-contained event: those credentials frequently grant access to Cisco Smart Account / Smart Licensing services and to integrated management planes, creating lateral paths into adjacent Cisco ecosystems.

Importantly, the source data does not disclose the specific mechanism. Statements about plaintext storage, unauthenticated API endpoints, or specific parameters would be speculative and are deliberately omitted here.

Exploitation Scenarios

No public proof-of-concept, Nuclei template, or exploit code is available for CVE-2026-76483, and CISA KEV does not list it. The attack chain below is described at the vulnerability-class level (CWE-522) and is inferred from the CVSS vector, not from disclosed implementation details.

1. Reconnaissance / target identification. An adversary enumerates internet- or intranet-reachable instances of Cisco License On-Prem / Smart Software Manager On-Prem. Because the product is typically deployed on customer-managed infrastructure rather than Cisco-hosted SaaS, organizational exposure varies widely; Shodan-style fingerprinting (HTTP titles and product strings) is the natural discovery method. The attacker's objective at this stage is simply to identify reachable management interfaces of the license platform.

2. Triggering the flaw class. The weakness class is insufficiently protected credentials. At this class level, exploitation involves interacting with an exposed network interface of the product in a way that causes credential material to be disclosed or altered — for example, retrieving credential data through an interface that does not enforce authentication (consistent with PR:N) or observing credential material in transit where protection is inadequate (consistent with AV:N). No specific endpoint, parameter, or request sequence can be asserted from the available data.

3. Payload / execution method. Because the advisory provides no endpoint-level detail, no request payload can be described. The relevant attacker capability is the ability to submit network requests to the affected service without prior authentication, and to receive or modify credential-related content as a result. Exploitation does not require user interaction (UI:N) or elevated privileges (PR:N).

4. Post-exploitation impact. With high confidentiality and integrity impact and no availability impact, the expected outcomes are (a) theft of credentials that can be reused against the license platform, its administrative interfaces, or connected Cisco Smart Account / Smart Licensing services, and (b) modification of credential or configuration data leading to unauthorized state changes. Stolen license-platform credentials are particularly valuable because they can enable entitlement manipulation, service disruption via license tampering, and lateral movement into integrated management systems. Availability is explicitly rated as not impacted, so destructive/denial-of-service outcomes are not the expected consequence of this specific CVE group.

Defenders should treat any unauthenticated read or write of credential-adjacent data from this product as a compromise event, not merely an information disclosure.

Impact Assessment

The CVSS v3.1 base score is 9.1 (Critical). Subscore interpretation:

• Exploitability subscore components: AV:N, AC:L, PR:N, UI:N — this is the maximum-exploitability configuration. No credentials, no user action, and no special network position are required.
• Impact subscore components: C:H, I:H, A:N — total loss of confidentiality and integrity of the vulnerable component's data, with no availability effect.
• Scope is Unchanged (S:U), so the direct impact is bounded to the vulnerable component; however, the unscopped downstream effect of credential theft in a license management platform routinely extends to Cisco Smart Account relationships and to neighboring management infrastructure.

Blast radius depends entirely on deployment exposure. Organizations that expose License On-Prem / SSM On-Prem to untrusted networks, flat internal networks, or partner/VPN segments face the greatest risk because PR:N means no foothold is required. Systems most at risk are the license management host itself, any services whose credentials are stored or brokered by it, and Cisco Smart Account / Smart Licensing administrative relationships. Business impact includes unauthorized license entitlement changes, compliance and audit exposure from credential compromise, and follow-on lateral movement using harvested secrets.

EPSS has not yet been scored by FIRST.org for this CVE; no exploitation-probability estimate should be quoted. CISA KEV status is NO, and no threat actor campaign or in-the-wild exploitation has been reported in the available data.

Detection Guidance

Sigma Rule

title: Suspicious Unauthenticated Access to Cisco License On-Prem Credential Resources
id: 8f3c1a94-2d77-4b0e-9c51-64a7d0e5f812
status: experimental
description: Detects anomalous unauthenticated or repeated requests against Cisco License On-Prem / Smart Software Manager On-Prem interfaces that may indicate exploitation of CWE-522 insufficiently protected credentials (CVE-2026-76483).
references:
  - https://nvd.nist.gov/vuln/detail/CVE-2026-76483
author: valtersit.com
date: 2026-01-01
tags:
  - attack.t1190
  - attack.credential_access
  - cve.2026.76483
logsource:
  category: webserver
detection:
  selection_path:
    cs-uri-stem|contains:
      - '/ssm'
      - '/onprem'
      - '/license'
      - '/api/'
  selection_status:
    sc-status:
      - 200
      - 401
      - 403
  selection_anon:
    cs-username: '-'
  timeframe: 5m
  condition: selection_path and selection_status and selection_anon | count() by c-ip > 50
falsepositives:
  - Health checks and monitoring probes from authorized management hosts
  - Load balancer or vulnerability scanner traffic
level: medium

YARA Rule

rule CVE_2026_76483_Cisco_License_OnPrem_Credential_Exposure
{
    meta:
        description = "Detects credential-related artifacts and License On-Prem / SSM On-Prem references in files and captures for CVE-2026-76483 (CWE-522)"
        author = "valtersit.com"
        date = "2026-01-01"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2026-76483"
        cve = "CVE-2026-76483"
        cwe = "CWE-522"

    strings:
        $p1 = "Smart Software Manager On-Prem" ascii nocase
        $p2 = "License On-Prem" ascii nocase
        $p3 = "ssm_onprem" ascii nocase
        $c1 = "password" ascii nocase
        $c2 = "passwd" ascii nocase
        $c3 = "client_secret" ascii nocase
        $c4 = "api_key" ascii nocase
        $c5 = "authorization: basic" ascii nocase

    condition:
        any of ($p*) and any of ($c*)
}

Suricata IDS Rule

alert http any any -> any any (msg:"CVE-2026-76483 Cisco License On-Prem Unauthenticated Credential Resource Access Attempt"; flow:established,to_server; http.method; content:"GET"; http.uri; content:"/"; pcre:"/(ssm|onprem|license|api)/Ui"; http.header; content:"Authorization"; negate; pcre:"/Accept\x3a\s*\x2a\/\x2a/i"; threshold:type both, track by_src, count 30, seconds 300; classtype:attempted-recon; reference:cve,2026-76483; reference:url,nvd.nist.gov/vuln/detail/CVE-2026-76483; sid:1007648301; rev:1;)

Elastic Detection

sequence by source.ip with maxspan=5m
  [ network where network.protocol == "http" and
      url.path : ("/ssm*", "/onprem*", "/license*", "/api/*") and
      http.response.status_code in (200, 401, 403) ]
  [ network where network.protocol == "http" and
      url.path : ("/ssm*", "/onprem*", "/license*", "/api/*") and
      http.response.status_code == 200 ]

Splunk SPL Query

index=web OR index=proxy sourcetype=access_combined OR sourcetype=stream:http
| eval uri_lower = lower(uri)
| where match(uri_lower, "(ssm|onprem|license|/api/)")
| eval is_anon = if(isnull(user) OR user="-" OR user="", 1, 0)
| stats count AS request_count, dc(uri) AS distinct_uris, values(status) AS statuses BY src_ip, is_anon
| where is_anon=1 AND request_count > 50
| eval severity = case(request_count > 500, "high", request_count > 100, "medium", true(), "low")
| table src_ip, is_anon, request_count, distinct_uris, statuses, severity
| sort - request_count

Wazuh OSSEC Rule

<group name="web,cve-2026-76483,credential_access,">
  <rule id="100830" level="8">
    <if_sid>31100</if_sid>
    <url>ssm|onprem|license|/api/</url>
    <description>CVE-2026-76483: Access to Cisco License On-Prem credential-adjacent resource detected</description>
    <group>cve_2026_76483,attack_t1190,</group>
  </rule>

  <rule id="100831" level="12" frequency="30" timeframe="300">
    <if_matched_sid>100830</if_matched_sid>
    <same_source_ip />
    <description>CVE-2026-76483: Repeated unauthenticated access to Cisco License On-Prem endpoints from same source - possible CWE-522 exploitation</description>
    <mitre>
      <id>T1190</id>
    </mitre>
    <group>cve_2026_76483,attack_t1190,</group>
  </rule>
</group>

Mitigation & Patch Guidance

Patch confidence: 0/4 (UNPATCHED — no patch evidence from any tracked source). No vendor fix identifier, affected version range, or workaround was included in the source data. The following guidance is therefore prioritized, defensive, and must be validated against Cisco's official advisory before implementation.

Immediate mitigations:

1. Reduce exposure. Restrict network access to the License On-Prem / SSM On-Prem management interface to a dedicated, allow-listed management segment or bastion hosts. Because the CVSS vector is AV:N/PR:N/UI:N, any reduction in network reachability directly reduces risk.
2. Enforce authentication at the perimeter. Where an authenticating reverse proxy can be placed in front of the management interface, require strong authentication for all access, so that unauthenticated requests (PR:N) cannot reach the product directly.
3. Encrypt and inspect transport. Terminate TLS with modern parameters at the edge, and verify that no credential-bearing traffic traverses untrusted segments in cleartext.
4. Monitor actively. Deploy the detection rules above and alert on unauthenticated or high-volume access to license/SSM endpoints, particularly from non-management source IPs.
5. Assume compromise discipline. If unauthenticated credential-adjacent access is observed, rotate credentials associated with the license platform and with any connected Cisco Smart Account / Smart Licensing relationships, and review audit logs for entitlement or configuration changes.

Patch / upgrade steps:

1. Monitor Cisco's security advisory channels for Cisco License On-Prem (formerly SSM On-Prem) hardening releases corresponding to CVE-2026-76483. Cisco stated the review "resulted in software hardening releases" — obtain the exact fixed release identifiers directly from Cisco, as none were provided in the source data.
2. Stage the hardening release in a non-production instance, validate license operations and Smart Account connectivity, then deploy during a maintenance window.
3. After upgrade, re-verify that the externally observed attack surface has shrunk and that authentication is enforced on all credential-adjacent interfaces.

Long-term hardening:

1. Treat license management platforms as tier-0 infrastructure: separate them from general user networks, apply least-privilege access, and require strong authentication and MFA for administrative use.
2. Inventory all instances of Cisco License On-Prem / SSM On-Prem, including forgotten or test deployments that may not receive updates.
3. Enforce credential hygiene: rotate secrets on a defined schedule, avoid reuse between license infrastructure and other systems, and store secrets in a managed vault rather than in configuration files where feasible.
4. Continuously fingerprint your own estate (using the Shodan-style queries in METADATA as a self-audit) to detect unintended internet exposure.

References

• NVD — CVE-2026-76483: https://nvd.nist.gov/vuln/detail/CVE-2026-76483
• MITRE CWE — CWE-522, Insufficiently Protected Credentials: https://cwe.mitre.org/data/definitions/522.html
• MITRE ATT&CK — T1190, Exploit Public-Facing Application: https://attack.mitre.org/techniques/T1190/
• FIRST — EPSS (no score currently published for this CVE): https://www.first.org/epss/
• CISA Known Exploited Vulnerabilities Catalog (CVE-2026-76483 not listed): https://www.cisa.gov/known-exploited-vulnerabilities-catalog

No public proof-of-concept, exploit code, Nuclei template, threat actor campaign, or in-the-wild exploitation evidence was available for CVE-2026-76483 at the time of writing.