BlackTreeIndependent security intelligence
← Back to the CVE catalogue
Full vulnerability report · 2026
CVE-2026-56451High confidence

A vulnerability has been identified in Opcenter X (All versions < V2604)

Siemens · Opcenter X

10.0CriticalCVSS 4.0
Recommended action
Within 72 hours

Critical technical impact with a remotely reachable, unauthenticated path; no CISA KEV confirmation is currently recorded.

Patch available
Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

1 current
SSA-096828 · CSAF 2.0 · revision 1 · interimSiemens ProductCERTSSA-096828: Token Invalidation Vulnerability in Opcenter X Before V2604
1 known affected

The vendor explicitly identifies these products as affected by this CVE.

  • Opcenter X < V2604
Summary
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.
Remediation
Update to V2604 or later version
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2026-43650

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 72 hours

Critical technical impact with a remotely reachable, unauthenticated path; no CISA KEV confirmation is currently recorded.

Patch available
01

What, why and how

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.

What

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.

Why

The product does not verify, or incorrectly verifies, the cryptographic signature for data.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

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.

Why

The product does not verify, or incorrectly verifies, the cryptographic signature for data.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Improper Verification of Cryptographic Signature → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Not a CVSS 4.0 base metric
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-347 ↗

CWE-347: Improper Verification of Cryptographic Signature. The product does not verify, or incorrectly verifies, the cryptographic signature for data.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:L/SC:L/SI:H/SA:H

Common Vulnerability Scoring System 4.0: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.ATNoneAttack requirements: No additional deployment or execution condition is required.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.VCHighVulnerable-system confidentiality: A successful attack can cause a major loss.VIHighVulnerable-system integrity: A successful attack can cause a major loss.VALowVulnerable-system availability: A successful attack can cause a limited loss.SCLowSubsequent-system confidentiality: A successful attack can cause a limited loss.SIHighSubsequent-system integrity: A successful attack can cause a major loss.SAHighSubsequent-system availability: A successful attack can cause a major loss.
Post-exploitation / living off the land
Stolen credentials, tokens and legitimate administration functions may provide continued access without deploying a large custom toolset.
NetworkUnauthenticatedCWE-347
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

NCSC-NL · Dutch · NCSC-2026-0229Kwetsbaarheden verholpen in Siemens producten

A vulnerability in Opcenter X versions before V2604 allows unauthenticated remote attackers to forge JWTs by exploiting improper JWT algorithm header validation, enabling authentication bypass and full user impersonation, including administrators.

Official advisory
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
Opcenter X < V2604
Fixed
No fixed version is explicitly recorded in the structured CVE data.
Action
Update to V2604 or later version
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 14 Jul 2026 · Last source change 14 Jul 2026, 14:30 UTC · CWE-347 · Improper Verification of Cryptographic Signature

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2026-43650
Product sourceVendor CSAF · Siemens ProductCERT
Remediation sourceVendor CSAF · Siemens ProductCERT
CWE sourceCNA
NVD statusNVD not scheduled

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates →

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
ENISA EUVD · EUVD-2026-43650↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2026-56451 · cve.blacktree.nl