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Guns CVE-2026-92600

| EUVDEUVD-2026-80858 HIGH
Missing Authorization (CWE-862)
2026-09-16 VulnCheck GHSA-9f7f-38p2-62c4
7.1
CVSS 4.0 · Vendor: VulnCheck
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Attack ChainAIDerived

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

  1. Access
    Obtain any valid login token
  2. Delivery
    Call /sysUser/page and /sysUser/detail
  3. Exploit
    Interceptor skips RBAC check
  4. Execution
    Enumerate all users' PII and roles
  5. Impact
    Target admins for escalation/phishing

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V8 - Authorization Authorization checks on every request
MITRE ATT&CK

1 technique across 1 tactic: Privilege Escalation

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

Requires the attacker to hold ANY valid Guns login token (PR:L authenticated session) - the flaw does not permit unauthenticated access. The specific limiting/enabling condition is code-level: the SysUserController /sysUser/detail and /sysUser/page handlers omit the requiredPermission annotation, so the TokenAndPermissionInterceptor performs no RBAC check on them; this affects default builds of Guns through 8.3.5 with no special configuration needed beyond a running instance and a valid account. Exploitation is limited only by needing that authenticated session and network reachability to the admin application; no user interaction, no admin privileges, and no non-default setting are required.

Impact

The vendor CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:L/UI:N/VC:H) scoring 7.1 is internally consistent with the description: a network-reachable flaw requiring only a low-privileged authenticated session (any valid login token) to read all users' PII with no user interaction. This is a genuine broken-access-control (CWE-862) issue, not a false-positive high-CVSS: the exploit is trivial (two GET-style endpoints missing a requiredPermission annotation) and the impact - full user directory including emails, phone numbers, last-login IPs, and role assignments - is a realistic mass-PII disclosure and recon aid for privilege escalation. However, real-world priority is tempered by missing/limiting signals: no EPSS score, no CISA KEV listing, and no public POC are present in the input, so exploitation is not confirmed active or automated at scale. Crucially, PR:L means the attacker must ALREADY hold a valid account, which bounds the population of exploiters to authenticated (possibly self-registered or low-tier) users. The confidentiality impact is real but scope is unchanged (SC/SI/SA:N) and there is no integrity or availability effect. Net: a credible, easily-exploited insider/low-privilege data-exposure bug, but not an unauthenticated internet-wide emergency.

Exploit ScenarioDerived

An attacker obtains any valid Guns login token - for example a low-privilege employee account or a self-registered user - and issues requests to /sysUser/page and /sysUser/detail, which lack the requiredPermission configuration so the TokenAndPermissionInterceptor skips RBAC checks. The response returns the full user roster (account names, real names, emails, phone numbers, last-login IPs, role assignments), which the attacker harvests for phishing, credential-stuffing, or targeting admin accounts. No public exploit is identified at time of analysis, but the attack requires no special tooling given the low CVSS complexity (AC:L).

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
No patch listed yet 0.3% exploitation probability (EPSS)

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AnalysisAIv1 – Sep 16, 2026

Missing authorization in the Guns Java rapid-development framework (through 8.3.5) allows any authenticated user to harvest the full user directory, including account names, real names, email addresses, phone numbers, last-login IPs and role assignments. The /sysUser/detail and /sysUser/page handlers in SysUserController omit the requiredPermission annotation, so the TokenAndPermissionInterceptor performs no RBAC check on them and returns data for every user in the system to anyone holding a valid login token. The attack is network-reachable and needs only a low-privileged authenticated session (PR:L), with no user interaction and no administrative rights; no public exploit code or confirmed active exploitation has been identified at time of analysis, and no EPSS score was supplied in the source data.

RemediationAI

No vendor-released patch was identified at time of analysis: the available references point to the upstream source repository, the specific interceptor source lines, the affected Maven artifact, and tracking issue https://github.com/stylefeng/Guns/issues/118 rather than to a tagged fixed release, so no patched version number can be cited and upgrades should be validated against the upstream issue before being treated as a fix. The direct code-level remedy is to add the requiredPermission annotation (matching the permission code used by the corresponding administrative menu/role) to the /sysUser/detail and /sysUser/page handlers in SysUserController and redeploy; the trade-off is that it requires rebuilding the application and can break any UI flow that legitimately rendered without that permission, so role mappings must be reviewed first. Until a fixed build is available, compensating controls include fronting the admin application with a reverse proxy or gateway rule that blocks or restricts /sysUser/detail and /sysUser/page to trusted administrator networks or identities (simple and immediately effective, but it degrades legitimate admin usability and is bypassable if the app is also reachable on another port or path), adding a custom servlet filter or interceptor that enforces an explicit role check on those two paths before the controller executes (effective but requires custom code maintenance outside the upstream codebase), and tightening account provisioning so that only vetted administrators receive valid Guns login tokens, since the flaw only requires any authenticated session (this limits blast radius but does not remove the underlying defect and can slow onboarding). Because exploitation yields PII and role assignments rather than write access, additional detection-oriented steps are worthwhile: enable and monitor access logging for /sysUser/page and /sysUser/detail, alert on bulk or sequential user enumeration, and rotate or invalidate existing sessions and API tokens if unauthorized reads are suspected, accepting that forced rotation is disruptive to active users.

Affected VersionsENISA

Guns 0 ≤8.3.5

Affected Packages

euvd guns 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

Guns (stylefeng/Guns) is a Java Spring Boot administration/scaffolding platform built on the vendor's 'Roses' component library, distributed in part as Maven artifacts such as com.javaguns.roses:system-business-hr:8.3.5. Authorization is annotation-driven: controller methods are expected to declare a requiredPermission value, and the TokenAndPermissionInterceptor (source reference src/main/java/cn/stylefeng/guns/core/security/TokenAndPermissionInterceptor.java, lines 110-119) reads that annotation to decide whether the caller's role set satisfies the required permission. When the annotation is absent, the interceptor's check is effectively skipped and the request proceeds with only token validity established. The root cause is therefore CWE-862 (Missing Authorization) rather than broken authentication: the attacker still needs to authenticate, but once inside, the missing permission metadata means the endpoints are not protected by RBAC. The supplied CPE cpe:2.3:a:stylefeng:guns:*:*:*:*:*:*:*:* uses a wildcard version, which, combined with the advisory wording 'through 8.3.5', indicates the exposure is present in default builds up to and including 8.3.5 with no special configuration required beyond a running instance and a valid account. Impact is confidentiality-only and high (VC:H): reads of user PII and role assignments, with no integrity or availability effect and no scope change in the independently assessed CVSS 3.1 vector (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N), which aligns with the vendor's CVSS 4.0 score of 7.1.

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Severity by source

Vendor (VulnCheck) PRIMARY 7.1 HIGH
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
vuln.today AI 6.5 MEDIUM

Network-reachable endpoints exploitable by any low-privileged authenticated user (PR:L) with no interaction; full user-PII disclosure gives C:H, with no integrity or availability impact.

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

Primary rating from Vendor (VulnCheck).

CVSS VectorVendor: VulnCheck

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
Low
User Interaction
None
Vulnerable system: Confidentiality
High
Vulnerable system: Integrity
None
Vulnerable system: Availability
None
Subsequent system: Confidentiality
None
Subsequent system: Integrity
None
Subsequent system: Availability
None

DescriptionCVE.org

Guns through 8.3.5 contains an information disclosure vulnerability in SysUserController where /sysUser/detail and /sysUser/page endpoints omit requiredPermission configuration, causing the permission interceptor to skip RBAC validation for authenticated users. Attackers with any valid login token can retrieve sensitive user information including account names, real names, email addresses, phone numbers, last login IPs, and role assignments for all users in the system.

Executive ViewAI

Why It Matters

The Guns Java rapid-development framework (versions through 8.3.5) contains a missing-authorization flaw that lets any user with a valid low-privileged login token pull the organization's entire user directory - real names, email addresses, phone numbers, last-login IP addresses and role assignments - from two unprotected administrative endpoints. Because the exposed data is a ready-made target list that reveals who holds privileged roles, leadership should treat this as both a privacy/regulatory exposure and a precursor risk to phishing, credential-stuffing and social-engineering attacks against the whole workforce. No vendor-released patch, public exploit code, or confirmed active exploitation was identified at time of analysis.

Business Impact: High
Compensating Controls

No vendor-released patch identified at time of analysis; interim mitigations include network-layer denial or allowlisting of /sysUser/detail and /sysUser/page at the reverse proxy, API gateway or WAF; adding the requiredPermission annotation directly to the SysUserController handlers as a custom code fix; restricting endpoint access to administrative roles; routing legitimate user lookups through a privileged, audited service account; log-based monitoring and alerting for bulk user-directory enumeration from low-privileged tokens; and token rotation for privileged accounts pending a vendor patch above version 8.3.5.

Threat Intelligence Overview

EPSS Score
0.3%
Top 75% exploitable
Prevalence
Low
Niche open-source Java/Spring Boot admin scaffold, mainly Chinese developer community
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 HIGH
CISA KEV No
Public POC No
EPSS 0.3%
Patch available No
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
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· derived
Scheduled
Exploitation· derived
None
System Exposure· derived
Open
Automatable· derived
No
Human Impact
High

Priority Score

36
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +36
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.

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

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