CVE-2026-11429

CRITICALCVSS 10/10EPSS 1.15%

Last modified

CVE-2026-11429 is a critical-severity vulnerability rated 10/10 on the CVSS scale. Two endpoints in the Vault Service ScriptsController, shared by Altium Enterprise Server and Altium 365, accept file uploads where a user-supplied filename component is used to construct the destination path without validation, allowing arbitrary files to be written to any location writable by the service account. Because the file write operation completes before authentication is validated, the vulnerability can be exploited without any credentials, session, or prior knowledge of the system. An unauthenticated network attacker can use this primitive to place executable content in directories where it is later executed by the service, resulting in remote code execution under the Vault Service account. EPSS estimates a 1.15% chance of exploitation in the next 30 days.

Description

Two endpoints in the Vault Service ScriptsController, shared by Altium Enterprise Server and Altium 365, accept file uploads where a user-supplied filename component is used to construct the destination path without validation, allowing arbitrary files to be written to any location writable by the service account. Because the file write operation completes before authentication is validated, the vulnerability can be exploited without any credentials, session, or prior knowledge of the system. An unauthenticated network attacker can use this primitive to place executable content in directories where it is later executed by the service, resulting in remote code execution under the Vault Service account. Altium Enterprise Server is fixed in 8.1.1; the issue has been remediated in Altium 365 (commercial and government cloud) at the service level.

Metrics

CVSS 4.0
10/10

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability
1.15%

63.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
AltiumAltium Enterprise Server< 8.1.1
AltiumAltium 365All versions

References

Timeline

Published
Last Modified
Status
Awaiting Analysis

Frequently Asked Questions

What is CVE-2026-11429?
Two endpoints in the Vault Service ScriptsController, shared by Altium Enterprise Server and Altium 365, accept file uploads where a user-supplied filename component is used to construct the destination path without validation, allowing arbitrary files to be written to any location writable by the service account. Because the file write operation completes before authentication is validated, the vulnerability can be exploited without any credentials, session, or prior knowledge of the system. An unauthenticated network attacker can use this primitive to place executable content in directories where it is later executed by the service, resulting in remote code execution under the Vault Service account. Altium Enterprise Server is fixed in 8.1.1; the issue has been remediated in Altium 365 (commercial and government cloud) at the service level.
How severe is CVE-2026-11429?
CVE-2026-11429 has a CVSS score of 10/10 (CRITICAL severity). The EPSS model estimates a 1.15% probability of exploitation in the next 30 days.
How do I fix CVE-2026-11429?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST