VulnerabilityPublished 27 Feb 2026Updated 2 Mar 2026

CVE-2026-21718: Copeland XWEB 300D PRO · Weak Cryptography

Affects Copeland XWEB 300D PROSource CVE Database V5

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Not known to be exploited · CVSS 10.0 Critical.

Data as of 29 Oct 2026, 19:04 UTC

CVSS 3.1 base score

10.0Critical

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.6% chance of exploitation in 30 days – higher than 52% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

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

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 27 Feb 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
CopelandCopeland XWEB 300D PRO	Affected <=1.12.1	Fixed in–
CopelandCopeland XWEB 500D PRO	Affected <=1.12.1	Fixed in–
CopelandCopeland XWEB 500B PRO	Affected <=1.12.1	Fixed in–

AI-suggested

Immediate network segmentation: Isolate Copeland XWEB 300D PRO devices from untrusted networks and limit access to trusted administrators only.
Implement strict firewall rules to restrict inbound and outbound traffic to and from the affected devices, allowing only necessary management protocols.
Deploy intrusion detection and prevention systems (IDS/IPS) with signatures or anomaly detection tuned to identify suspicious activity targeting Copeland XWEB 300D PRO.
Monitor device logs and network traffic for unusual authentication bypass attempts or unexpected code execution behaviors.
Use VPNs or secure tunnels for remote access to the devices to add an additional layer of authentication and encryption.
Engage with Copeland support or vendor channels to obtain updates on patch availability and apply patches immediately once released.
Conduct thorough risk assessments and consider temporary decommissioning or replacement of vulnerable devices in critical environments until a fix is available.
Educate operational technology (OT) staff about the vulnerability and enforce strict access control policies.
Maintain regular backups of device configurations and system states to enable rapid recovery in case of compromise.
Consider deploying endpoint detection and response (EDR) solutions tailored for industrial control systems to detect post-exploitation activities.

Description

An authentication bypass vulnerability exists in Copeland XWEB Pro version 1.12.1 and prior, enabling any attackers to bypass the authentication requirement and achieve pre-authenticated code execution on the system.

Impact

The impact of CVE-2026-21718 is severe and far-reaching for organizations using Copeland XWEB 300D PRO devices. Successful exploitation allows attackers to bypass authentication and execute arbitrary code with high privileges, potentially leading to full system compromise. This can result in unauthorized control over industrial processes, data exfiltration, manipulation of operational parameters, and disruption of critical infrastructure services. The confidentiality, integrity, and availability of the affected systems are all at high risk. Given the device's role in industrial environments, exploitation could cause physical damage, safety hazards, and significant operational downtime. The lack of available patches increases the window of exposure, raising the urgency for organizations to implement alternative mitigations. The vulnerability's network accessibility and no requirement for user interaction make it highly exploitable by remote attackers, increasing the likelihood of widespread attacks once exploit code becomes available. Overall, this vulnerability poses a critical threat to industrial control systems and organizations relying on Copeland XWEB 300D PRO for operational technology.

CWE-327Use of a Broken or Risky Cryptographic Algorithm (opens in a new tab)
Class weaknessLikelihood of exploit: HighOWASP Top 10 A04:2025: Cryptographic Failures (opens in a new tab)
The product uses a broken or risky cryptographic algorithm or protocol.
Architecture and Design · Libraries or Frameworks
When there is a need to store or transmit sensitive data, use strong, up-to-date cryptographic algorithms to encrypt that data. Select a well-vetted algorithm that is currently considered to be strong by experts in the field, and use well-tested implementations.
Architecture and Design
Ensure that the design allows one cryptographic algorithm to be replaced with another in the next generation or version. Where possible, use wrappers to make the interfaces uniform. This will make it easier to upgrade to stronger algorithms.
Architecture and Design
Carefully manage and protect cryptographic keys (see CWE-320). If the keys can be guessed or stolen, then the strength of the cryptography itself is irrelevant.
OWASP Cheat Sheets
Cryptographic Storage (opens in a new tab)
Key Management (opens in a new tab)
Transport Layer Protection (opens in a new tab)
User Privacy Protection (opens in a new tab)
Password Storage (opens in a new tab)
OWASP ASVS 4.0.3
V8.3.7 (opens in a new tab)
V2.9.3 (opens in a new tab)
V6.2.2 (opens in a new tab)
Attack patterns
Encryption Brute Forcing (opens in a new tab)
Creating a Rogue Certification Authority Certificate (opens in a new tab)
Signature Spoof (opens in a new tab)
Signature Spoofing by Improper Validation (opens in a new tab)
Cryptanalysis of Cellular Encryption (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 6 Mar 2026, 21:30 UTC

WeaknessesCWE-327

Technical details

References

Community reviews

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