Evidence used
- No CISA KEV confirmation is currently recorded.
- A structured source references public exploit or proof-of-concept material.
- EPSS is 0.45% for the current model date.
BlackTreeCVE IntelligenceFull vulnerability report · 2026
CVE-2026-24068High confidence
Missing XPC Client & NSXPC endpoint validation leads to privilege escalation in Vienna Assistant (MacOS) - Vienna Symphonic Library
Vienna Symphonic Library GmbH · Vienna Assistant
8.8HighCVSS 3.1
Within 7 days
Patch availableHigh technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.
R
Open reassessment dashboard →Operational reassessment
Published severity in operational context
Published severityHigh→Operational priority:Critical, raised one band.upgradedsince 3 Apr 2026
Compensating controls
- Validate the affected product branch and deploy the verified fixed release.
- Restrict the affected network interface to trusted sources where business-safe.
- Increase monitoring for the attack path and post-exploitation behaviour described in the report.
Verification
- Confirm that the asset runs Vienna Symphonic Library GmbH Vienna Assistant and falls inside the recorded affected range.
- Verify the installed build against the product-specific fixed version after deployment.
- Validate exposure, authentication requirements and compensating controls in the actual environment.
- Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
High technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.
Patch available01
What, why and how
The VSL privileged helper does utilize NSXPC for IPC. The implementation of the "shouldAcceptNewConnection" function, which is used by the NSXPC framework to validate if a client should be allowed to connect to the XPC listener, does not validate clients at all. This means that any process can connect to this service using the configured protocol. A malicious process is able to call all the functions defined in the corresponding HelperToolProtocol. No validation is performed in the functions "writeReceiptFile" and “runUninstaller” of the HelperToolProtocol. This allows an attacker to write files to any location with any data as well as execute any file with any arguments. Any process can call these functions because of the missing XPC client validation described before. The abuse of the missing endpoint validation leads to privilege escalation.
What
The VSL privileged helper does utilize NSXPC for IPC. The implementation of the "shouldAcceptNewConnection" function, which is used by the NSXPC framework to validate if a client should be allowed to connect to the XPC listener, does not validate clients at all. This means that any process can connect to this service using the configured protocol. A malicious process is able to call all the functions defined in the corresponding HelperToolProtocol. No validation is performed in the functions "writeReceiptFile" and “runUninstaller” of the HelperToolProtocol. This allows an attacker to write files to any location with any data as well as execute any file with any arguments. Any process can call these functions because of the missing XPC client validation described before. The abuse of the missing endpoint validation leads to privilege escalation.
Why
A security-sensitive function is reachable without the authentication check that should protect it.
How
An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may gain additional privileges.
What
The VSL privileged helper does utilize NSXPC for IPC. The implementation of the "shouldAcceptNewConnection" function, which is used by the NSXPC framework to validate if a client should be allowed to connect to the XPC listener, does not validate clients at all. This means that any process can connect to this service using the configured protocol. A malicious process is able to call all the functions defined in the corresponding HelperToolProtocol. No validation is performed in the functions "writeReceiptFile" and “runUninstaller” of the HelperToolProtocol. This allows an attacker to write files to any location with any data as well as execute any file with any arguments. Any process can call these functions because of the missing XPC client validation described before. The abuse of the missing endpoint validation leads to privilege escalation.
Why
A security-sensitive function is reachable without the authentication check that should protect it.
How
An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may gain additional privileges.
02
Exploit reality and attack path
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
Observed exploitation No confirmed evidence
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.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 Reference recorded
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.CISA Vulnrichment records proof-of-concept exploitation in its SSVC data. BlackTree has not independently executed or validated exploit material.
- Likely attack path
- a network path → Missing Authentication for Critical Function → gain additional privileges
- Attack surface
- Network
- Privileges required
- Low: a basic authenticated account is required
- User interaction
- None
- Attack complexity
- Low: no specialised conditions are recorded
- Security boundary
- Unchanged: impact remains within the vulnerable component's security authority
- Weakness
?
CWE means Common Weakness Enumeration: a standard category for the underlying weakness. - CWE-306 ↗
CWE-306: Missing Authentication for Critical Function. The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.
- CVSS vector
?
CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity. CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HCommon Vulnerability Scoring System 3.1: 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.PRLowPrivileges required: The attacker needs basic user-level privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.AHighAvailability impact: A successful attack can cause a major loss.- Post-exploitation / living off the land
- No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
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
- Vienna Assistant: 1.2.542
- Action
- Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
- 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 26 Mar 2026 · Last source change 3 Apr 2026, 05:33 UTC · CWE-306 · Missing Authentication for Critical Function
CVE recordCVE.org · 5.2
CVSS sourceCISA ADP
EPSS source FIRST · tracked since 2026-08-14
?
The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.European sourceENISA EUVD · EUVD-2026-16160
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD not scheduled
Core structured fields are present and their contributing authorities are shown above.
Material change intelligence
View recent updates ↗What changed after publication
No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.
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.