How severe is CVE-2026-21718?

CVE-2026-21718 has a CVSS 3.x base score of 10.0, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-21718 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (34th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-21718?

CVE-2026-21718 primarily affects Copeland Xweb 300d Pro Firmware. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-21718?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2026-21718 have an EU (EUVD) identifier?

Yes. CVE-2026-21718 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-8947.

When was CVE-2026-21718 published?

CVE-2026-21718 was published on 2026-02-27 and last updated on 2026-06-17.

CVE-2026-21718

CVE-2026-21718 is a critical-severity vulnerability in Copeland Xweb 300d Pro Firmware with a CVSS 3.x base score of 10.0. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-327.

Key facts

Severity: Critical (CVSS 3.x base score 10.0)
EPSS exploit prediction: 0% (34th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-8947
Weakness: CWE-327
Affected product: Copeland Xweb 300d Pro Firmware
Published: 2026-02-27
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2026-21718?: 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.
How severe is CVE-2026-21718?: CVE-2026-21718 has a CVSS 3.x base score of 10.0, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-21718 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (34th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-21718?: CVE-2026-21718 primarily affects Copeland Xweb 300d Pro Firmware. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-21718?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-21718 have an EU (EUVD) identifier?: Yes. CVE-2026-21718 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-8947.
When was CVE-2026-21718 published?: CVE-2026-21718 was published on 2026-02-27 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:o:copeland:xweb_300d_pro_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:copeland:xweb_500d_pro_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:copeland:xweb_500b_pro_firmware:*:*:*:*:*:*:*:*

More vulnerabilities in Copeland Xweb 300d Pro Firmware

CVE-2026-24663 — Critical (CVSS 9.0): An OS command injection vulnerability exists in XWEB Pro version 1.12.1 and prior, enabling an unauthenticated…
CVE-2026-25085 — High (CVSS 8.6): A vulnerability exists in Copeland XWEB Pro version 1.12.1 and prior, in which an unexpected return value from the…
CVE-2026-3037 — High (CVSS 8.0): An OS command injection vulnerability exists in XWEB Pro version 1.12.1 and prior, enabling an authenticated attacker…
CVE-2026-25721 — High (CVSS 8.0): An OS command injection vulnerability exists in XWEB Pro version 1.12.1 and prior, enabling an authenticated attacker…
CVE-2026-25196 — High (CVSS 8.0): An OS command injection vulnerability exists in XWEB Pro version 1.12.1 and prior, enabling an authenticated attacker…
CVE-2026-25105 — High (CVSS 8.0): An OS command injection vulnerability exists in XWEB Pro version 1.12.1 and prior, enabling an authenticated…

All CVEs affecting Copeland Xweb 300d Pro Firmware →

Other CWE-327 (Use of a Broken or Risky Cryptographic Algorithm) vulnerabilities

CVE-2026-50086 — Critical (CVSS 10.0): The Aqara IAM/SSO gateway (gw-builder.aqara.com) exposes bidirectional AES round-trups against the platform's signing…
CVE-2025-54426 — Critical (CVSS 9.9): Polkadot Frontier is an Ethereum and EVM compatibility layer for Polkadot and Substrate. In versions prior to commit…
CVE-2024-51478 — Critical (CVSS 9.9): YesWiki is a wiki system written in PHP. Prior to 4.4.5, the use of a weak cryptographic algorithm and a hard-coded…
CVE-2026-28252 — Critical (CVSS 9.8): A Use of a Broken or Risky Cryptographic Algorithm vulnerability in Trane Tracer SC, Tracer SC+, and Tracer Concierge…
CVE-2025-13476 — Critical (CVSS 9.8): Rakuten Viber Cloak mode in Android v25.7.2.0g and Windows v25.6.0.0–v25.8.1.0 uses a static and predictable TLS…
CVE-2025-69929 — Critical (CVSS 9.8): An issue in N3uron Web User Interface v.1.21.7-240207.1047 allows a remote attacker to escalate privileges via the…

Browse all CWE-327 (Use of a Broken or Risky Cryptographic Algorithm) vulnerabilities →