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Cisco License On-Prem EUVDEUVD-2026-94465

| CVE-2026-76482 CRITICAL
Improper Verification of Cryptographic Signature (CWE-347)
2026-10-07 cisco GHSA-hg4w-vv9x-vfc5
10.0
CVSS 3.1 · Vendor: cisco
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Reach SSM On-Prem management interface
  2. Delivery
    Craft JWT with forged signature
  3. Exploit
    Bypass signature verification
  4. Execution
    Assume trusted/admin identity
  5. Impact
    Access sensitive data and control server

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A04:2025 - Cryptographic Failures
ASVS 5.0
V11 - Cryptography Signature verification
Exploitation Conditions

Exploitation targets the server's cryptographic signature verification (CWE-347) of tokens - consistent with the 'Jwt Attack' tag, a crafted JWT whose signature is not properly validated is accepted as authentic. Per the CVSS vector (PR:N/UI:N/AC:L), no authentication, no user interaction, and low complexity are required against a network-reachable Cisco License On-Prem / SSM On-Prem instance. The primary limiting factor is network exposure: risk is concentrated where the management/licensing interface is reachable by the attacker (internet-facing or lateral network access), and the precise affected versions are not specified in the available data, so instances already on the hardening release are not vulnerable.

Impact

All severity signals point to maximum theoretical risk: the CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H) scores a perfect 10.0, indicating remote, unauthenticated, low-complexity exploitation with a scope change and total compromise of confidentiality, integrity, and availability. CWE-347 (improper verification of a cryptographic signature) combined with the 'Jwt Attack' tag strongly implies a JWT/token signature-verification bypass enabling authentication bypass. However, the real-world exploitation signals are notably absent or unverified: no EPSS probability was supplied, there is no CISA KEV listing, and no public proof-of-concept was provided - so there is no public exploit identified at time of analysis. The CVE text is also unusually vague ('improper input verification grouped under CWE-347' across 'multiple internally discovered vulnerabilities'), meaning the 10.0 reflects a vendor worst-case grouping from an internal security review rather than observed attacks. Net: treat as a high-priority patch item because the product is a trust/licensing authority and the flaw class is auth-bypass-shaped, but note that no evidence of active or at-scale exploitation exists yet, so the practical risk today is driven by exposure (internet-reachable instances) rather than confirmed weaponization.

Exploit ScenarioDerived

An unauthenticated attacker with network reach to a Cisco License On-Prem (SSM On-Prem) instance forges or tampers with a JWT whose signature is improperly verified, causing the server to accept the attacker as a trusted/administrative identity. With the authentication boundary bypassed and a scope change in play, the attacker reads sensitive licensing/identity data and manipulates the server. No public proof-of-concept is currently identified, so exploitation would require independent weaponization of the signature-verification flaw.

Act Now Prioritize within 24-48h. Why: CRITICAL severity.
No patch listed yet 0.2% exploitation probability (EPSS)

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AnalysisAIv1 – Oct 07, 2026

Unauthenticated remote attackers can bypass the cryptographic signature verification on authentication tokens in Cisco License On-Prem (formerly Cisco Smart Software Manager On-Prem, SSM On-Prem), so a forged JSON Web Token is accepted as authentic and the licensing server can be fully compromised; the CVSS 3.1 vector AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H yields a 10.0, meaning no credentials and no user interaction are required, low complexity, a scope change, and high impact to confidentiality, integrity and availability. Cisco's internal hardening review addressed this together with other internally discovered issues, and the advisory-linked hardening releases are the fix path, with no exact patched version numbers disclosed in the available data; the practical limiting factor is network exposure of the management/licensing interface, since the attacker must be able to reach the instance. No CISA KEV entry exists and no public exploit code has been identified at time of analysis, so this is a maximum-severity but not yet observed-exploited issue.

RemediationAI

Apply the vendor hardening release described in the Cisco security advisory (https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-hardening-ssm-Ph77wdhf), which is Cisco's patch path for this internally discovered issue; no exact fixed version string is provided in the available data, so follow the advisory's product-version mapping rather than a guessed build number. Until the hardening release is installed, reduce exposure by blocking untrusted network access to the License On-Prem / SSM On-Prem management and licensing interfaces - firewall or ACL restrictions to trusted administrative subnets, removing any internet-facing exposure, and segmenting the server from less-trusted networks - with the trade-off that this breaks remote/satellite licensing operations and remote administration until access is re-permitted. As an additional compensating control on systems that may have been reachable, rotate any token-signing keys and secrets and invalidate existing issued tokens so previously forged or captured tokens cannot be reused, understanding that this forces re-registration/re-authentication of licensing clients and may briefly interrupt license check-ins. There is no vendor-released patch alternative to the hardening release identified in the input data; monitor the advisory for updated version guidance and review authentication/token logs for anomalous or forged-token activity. Patch status: Patch available per vendor advisory.

Affected VersionsENISA

Cisco License On-Prem 8-202008
Cisco License On-Prem 9-202502
Cisco License On-Prem 8-202308
Cisco License On-Prem 1.1
Cisco License On-Prem 8-202108
Cisco License On-Prem 9-202501
Cisco License On-Prem 8-202304
Cisco License On-Prem 8-202012
Cisco License On-Prem 8-202302
Cisco License On-Prem 9-202601
Cisco License On-Prem 9-202504
Cisco License On-Prem 9-202412
Cisco License On-Prem 9-202510
Cisco License On-Prem 8-202112
Cisco License On-Prem 1.3
Cisco License On-Prem 8-202303
Cisco License On-Prem 10-202608
Cisco License On-Prem 9-202507
Cisco License On-Prem 9-202201
Cisco License On-Prem 8-202212
Cisco License On-Prem 8-202206
Cisco License On-Prem 10-202606
Cisco License On-Prem 9-202407
Cisco License On-Prem 9-202406
Cisco License On-Prem 1.4
Cisco License On-Prem 8-202010
Cisco License On-Prem 8-202201
Cisco License On-Prem 8-202105
Cisco License On-Prem 6.3.0
Cisco License On-Prem 1.2
Cisco License On-Prem 8-202004
Cisco License On-Prem 8-202006
Cisco License On-Prem 8-202401
Cisco License On-Prem 8-202404
Cisco License On-Prem 7-202001
Cisco License On-Prem 8-202102
Cisco License On-Prem 9-202410

Affected Packages

euvd cisco_license_on_prem no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

CWE-347 (Improper Verification of Cryptographic Signature) is the root-cause class here: the product validates tokens used for authentication and authorization but does not correctly verify the signature that binds the token to a trusted signer, a pattern consistent with the 'Jwt Attack' tag in the intelligence feed - for example algorithm-confusion or unsigned-token acceptance where the server trusts the token's own header to choose the verification algorithm, or otherwise fails to enforce the expected key. Because the CVSS vector carries PR:N and UI:N, the vulnerable code path is reachable by an unauthenticated network client with no user interaction, and S:C indicates the compromise escapes the vulnerable component's security scope, so a forged-token administrator session on the licensing server can affect the broader Cisco Smart Licensing trust relationships and the managed devices that consume licenses from it. The CPE string cpe:2.3:a:cisco:cisco_license_on-prem:*:*:*:*:*:*:*:* confirms the affected artifact is the Cisco License On-Prem software itself and is version-agnostic in the supplied data, meaning the precise vulnerable version window is not published in the available references; instances already running the hardening release described in the Cisco advisory are not affected.

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Severity by source

Vendor (cisco) PRIMARY 10.0 CRITICAL
AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
vuln.today AI 10.0 CRITICAL

Signature-verification bypass (CWE-347/JWT) is remotely reachable with no auth or interaction and yields an auth/trust-boundary break, justifying AV:N/AC:L/PR:N/UI:N/S:C and full C:H/I:H/A:H.

3.1 AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

Primary rating from Vendor (cisco).

CVSS VectorVendor: cisco

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

DescriptionCVE.org

As part of Cisco's ongoing commitment to proactive security and product quality, the engineering team for Cisco License On-Prem, formerly Cisco Smart Software Manager On-Prem (SSM On-Prem), has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities.

The vulnerabilities tracked by CVE-2026-76482 are related to issues with improper input verification that are grouped under the Common Weakness Enumeration (CWE) Pillar CWE-347.

Executive ViewAI

Why It Matters

Cisco License On-Prem (formerly Cisco Smart Software Manager On-Prem) is affected by a critical unauthenticated remote token-signature bypass that can allow full compromise of the licensing server. Because the flaw requires no credentials or user interaction and has high confidentiality, integrity, and availability impact, any broadly reachable instance poses a severe risk to licensing continuity, sensitive data, and dependent business operations. No vendor-released patch is identified at time of analysis and no public exploit has been identified, so leadership should prioritize immediate reduction of network exposure while Cisco hardening releases are tracked.

Business Impact: Severe
Compensating Controls

No vendor-released patch identified at time of analysis; restrict network reachability to the management/licensing interface to trusted administrative networks only, remove internet exposure, segment the appliance from production, enforce firewall/ACL/VPN allowlists, monitor for forged-token or unexpected licensing changes, and apply Cisco advisory-linked hardening releases once available.

Threat Intelligence Overview

EPSS Score
0.2%
Top 91% exploitable
Prevalence
Medium
enterprise Cisco licensing appliance, common in Cisco shops but not everywhere
Social Media
4
Sightings
Data Quality
5 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity CRITICAL
CISA KEV No
Public POC No
EPSS 0.2%
Patch available No
Active threat No
Deciding rule
CRITICAL severity
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision
Out-of-Cycle
Exploitation
None
System Exposure· derived
Open
Automatable
Yes
Human Impact
Very High
Technical Impact
Total

Priority Score

50
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +50
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.

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