How severe is CVE-2026-56451?

CVE-2026-56451 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-2026-56451 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (23rd percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-56451?

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.

When was CVE-2026-56451 published?

CVE-2026-56451 was published on 2026-07-14 and last updated on 2026-07-15.

CVE-2026-56451

CVE-2026-56451 is a critical-severity vulnerability 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-347.

Key facts

Severity: Critical (CVSS 3.x base score 10.0)
CVSS v4: 10.0
EPSS exploit prediction: 0% (23rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-347
Published: 2026-07-14
Last modified: 2026-07-15

Description

A vulnerability has been identified in Opcenter X (All versions < V2604). Affected applications do not properly validate the algorithm specified in the JSON Web Token (JWT) header. This could allow an unauthenticated remote attacker to forge arbitrary JWT, bypass authentication mechanisms and impersonate any user including administrative accounts, potentially gaining full unauthorized access to the application.

Frequently asked questions

What is CVE-2026-56451?: A vulnerability has been identified in Opcenter X (All versions < V2604). Affected applications do not properly validate the algorithm specified in the JSON Web Token (JWT) header. This could allow an unauthenticated remote attacker to forge arbitrary JWT, bypass authentication mechanisms and impersonate any user including administrative accounts, potentially gaining full unauthorized access to the application.
How severe is CVE-2026-56451?: CVE-2026-56451 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-2026-56451 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (23rd percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-56451?: 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.
When was CVE-2026-56451 published?: CVE-2026-56451 was published on 2026-07-14 and last updated on 2026-07-15.

References

https://cert-portal.siemens.com/productcert/html/ssa-096828.html

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