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Sunhillo SureLine CVE-2026-112352

| EUVDEUVD-2026-111360 CRITICAL
Reliance on Cookies without Validation and Integrity Checking (CWE-565)
2026-10-27 VulnCheck GHSA-rvgw-426x-67hr
9.1
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
    Reach SureLine web interface over network
  2. Exploit
    Forge session cookie with cleartext username 'Admin'
  3. Execution
    Satisfy checkLogin in libwebcmn.so and networkDiag.cgi
  4. Impact
    Execute arbitrary commands as root

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A08:2025 - Software or Data Integrity Failures
ASVS 5.0
V3 - Web Frontend Security Cookie integrity validation
Exploitation Conditions

The attacker must be able to reach the SureLine web interface over the network; no credentials are required (PR:N). The specific prerequisite from the description is that a target account must have an ACTIVE web session at the time of the attack - the forged cookie impersonates 'any user with an active web session,' so a live session for the chosen username (e.g. Admin or sftp_user) must exist; this is the AT:P attack requirement and the main limiting factor. The exploit primitive is a session cookie containing only a cleartext username with no random session identifier and no integrity protection, accepted by checkLogin in libwebcmn.so and networkDiag.cgi. Attacker must also know or guess a valid username, which is eased by documented default account names (Admin, sftp_user). Applies to SureLine versions 8.0.0 through below 9.1.5; upgrading to 9.1.5 is the vendor fix.

Impact

This is a genuine high-priority issue, not a high-CVSS/low-real-risk artifact. The CVSS 4.0 vector (AV:N/AC:L/AT:P/PR:N/UI:N, VC:H/VI:H) scores 9.1 and describes a network-reachable, unauthenticated (PR:N) authentication bypass that chains to root command execution - a near-complete compromise of the appliance. The vulnerability class (CWE-565, reliance on an unprotected cookie for a security decision) is trivially understood and the exploit primitive is a single forged cookie containing a cleartext username, so weaponization requires minimal skill. Multiple signals reinforce urgency: the vuln.today Decision label is act_now, a vendor patch is available, and VulnCheck is the reporting source. Two signals temper the picture and should be stated explicitly: this CVE is NOT listed in CISA KEV in the provided data, and no EPSS probability was supplied - so there is no confirmation of active or widespread in-the-wild exploitation; the act_now priority is driven by severity and ease of exploitation rather than observed attacks. The one real constraint is AT:P (attack requirement present): the description says the attacker impersonates a user 'with an active web session,' meaning a valid session for the forged username (e.g. Admin) must be live at the time of the forgery - a precondition outside the attacker's direct control, though easily met on an appliance where an admin is commonly logged in. Net: treat as act_now and patch immediately, while noting active exploitation is not independently confirmed here.

Exploit ScenarioDerived

An unauthenticated attacker who can reach the SureLine web interface guesses a default account name such as Admin or sftp_user and submits an HTTP request carrying a forged session cookie that is just that cleartext username, with no random session identifier or integrity check. Because checkLogin (libwebcmn.so) and networkDiag.cgi accept this unprotected cookie as a valid session, the attacker is authenticated as that user and chains the access into command execution as root. No public exploit is identified in the provided data, but the technique is simple enough to reproduce from the description alone.

Act Now Prioritize within 24-48h. Why: CRITICAL severity.
Patch available 1.3% exploitation probability (EPSS)

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AnalysisAIv1 – Oct 28, 2026

Sunhillo SureLine deployments running versions 8.0.0 through below 9.1.5 accept session cookies that contain nothing but a cleartext username, letting an unauthenticated remote attacker impersonate a logged-in user and chain that access into root command execution through networkDiag.cgi. The main limiting prerequisite is that the targeted account must already hold an active web session at attack time, and default account names such as Admin or sftp_user make the username guesswork trivial. The vendor has released SureLine 9.1.5 as the fix and prioritization guidance marks this as act_now; no CISA KEV listing or verified working exploit code is present in the available data.

RemediationAI

Upgrade SureLine to 9.1.5 or later, the version the vendor identifies as the fix, and confirm the installed build against the product page at https://www.sunhillo.com/product/sureline/ and the VulnCheck advisory at https://www.vulncheck.com/advisories/sunhillo-sureline-authentication-bypass-via-session-cookie. Because the weakness is the cookie format itself (a bare cleartext username with no random identifier or integrity protection), the complete fix comes from the vendor update rather than configuration hardening alone. Until the update is applied, reduce exposure by restricting network access to the SureLine web interface so only trusted management hosts can reach it, and by eliminating idle or lingering logged-in web sessions for default and service accounts such as Admin and sftp_user, since a forged cookie is only accepted while the matching account has an active session; the trade-off is that session timeouts and access restrictions interrupt legitimate administrative workflows and must be balanced against operational needs. There is no CISA KEV entry or verified working exploit code in the available data, but prioritization guidance marks the issue act_now, so treat the upgrade as urgent.

Affected VersionsENISA

SureLine 8.0.0 <9.1.5

Affected Packages

euvd sureline fix: 9.1.5

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

The flaw is a use of a credential-free authentication mechanism, categorized as CWE-565 (Reliance on Cookies without Validation and Integrity Checking). SureLine's web tier, implemented in libwebcmn.so and the networkDiag.cgi endpoint, builds its login decision from a cookie whose payload is the plaintext username with no random session identifier and no signature, MAC or encryption protecting the value. Because the cookie carries no server-issued secret, the login check in checkLogin cannot distinguish a forged cookie from a legitimate one as long as the submitted username corresponds to an account that currently has an active web session - that live-session dependency is the AT:P precondition in the assessed vector. The username space is small and partly documented (Admin, sftp_user), so the attacker only needs to enumerate likely account names and replay a crafted cookie. Success escalates beyond the web interface: the advisory states the bypass chains into root command execution, meaning the compromised web context reaches privileged OS-level command invocation. The assessed CVSS:3.1 vector (AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H) reflects network reachability without credentials, with the high attack complexity attributable to the requirement that a matching session already be live; the CPE cpe:2.3:a:sunhillo_corporation:sureline:*:*:*:*:*:*:*:* and EUVD range of 8.0.0 up to but excluding 9.1.5 define the exposure window.

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Severity by source

Vendor (VulnCheck) PRIMARY 9.1 CRITICAL
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
vuln.today AI 8.1 HIGH

Network-reachable and unauthenticated (AV:N/PR:N); AC:H because exploitation needs a victim account to have a live session (the AT:P requirement); root command execution yields full C/I/A impact.

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

Primary rating from Vendor (VulnCheck).

CVSS VectorVendor: VulnCheck

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

Lifecycle Timeline

2
Patch available
Oct 27, 2026 - 20:03 EUVD
CVE Published
Oct 27, 2026 - 19:43 cve.org
CRITICAL 9.1

DescriptionCVE.org

Sunhillo SureLine before 9.1.5 contains an authentication bypass vulnerability that allows an unauthenticated remote attacker to impersonate any user with an active web session by forging a session cookie containing only a cleartext username with no random identifier or integrity protection. Attackers can guess default account names such as Admin or sftp_user and submit a forged username cookie to satisfy the login check in checkLogin (libwebcmn.so) and networkDiag.cgi, chaining into root command execution.

Executive ViewAI

Why It Matters

Sunhillo SureLine versions 8.0.0 through 9.1.4 contain a critical authentication bypass (CVE-2026-112352, CVSS 9.1) that allows an unauthenticated remote attacker to impersonate a logged-in user and escalate to root command execution. This puts any organization relying on affected SureLine appliances at risk of full system compromise, potentially leading to data breach, operational disruption, and regulatory exposure. Leadership should prioritize immediate remediation because the vulnerability is trivial to exploit and default account names make attacks easy.

Business Impact: Severe
Compensating Controls

Apply vendor patch.

Threat Intelligence Overview

EPSS Score
1.3%
Top 29% exploitable
Prevalence
Low
niche air-traffic/surveillance data appliance, industry-specific vendor footprint
Data Quality
4 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 1.3%
Patch available Yes
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· derived
Scheduled
Exploitation· derived
None
System Exposure· derived
Open
Automatable· derived
Yes
Human Impact
Very High

Priority Score

47
Low Medium High Critical
KEV: 0
EPSS: +1
CVSS: +46
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.

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