CVE-2026-11420: Two path traversal vulnerabilities in the Network Installation Service (NIS) of Altium Enterprise Server allow

Q: How do I fix CVE-2026-11420?

on-prem enterprise server: upgrade to 8.1.1. Exact commands for each OS are on this page.

Q: Is CVE-2026-11420 being exploited?

CVE-2026-11420 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-11420 affect?

CVE-2026-11420 affects on-prem enterprise server. Severity is critical (CVSS 9.8). Two path traversal vulnerabilities in the Network Installation Service (NIS) of Altium Enterprise Server allow an unauthenticated network attacker to write arbitrary files to any writable location on the server filesystem and to read packag

Q: How urgent is CVE-2026-11420?

Priority 53/100. Critical severity; Remotely exploitable, no login, no user action

This month

CRITICAL 9.8REMOTEUPGRADE

CVE-2026-11420 is a critical-severity flaw (CVSS 9.8) affecting on-prem enterprise server. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Two path traversal vulnerabilities in the Network Installation Service (NIS) of Altium Enterprise Server allow an unauthenticated network attacker to write arbitrary files to any writable location on the server filesystem and to read package archive files from the server. No authentication, session, or credentials are required. Because content-controlled files can be written to web-accessible directories, or used to overwrite application bina

Why this priority

Critical severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.7% (top 47%)
CISA exploited list	No
Weakness	CWE-22, CWE-306
Published	2026-06-05
Last modified	2026-07-23

Publisher (CNA): Altium · Vendor: altium

Last updated 2026-07-23 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-06-05 20:17 UTCPublished CVE record published
2026-07-23 07:10 UTCUpdated Record last modified

altium on-prem enterprise server UPGRADE

Affected: < 8.1.1

Fixed in: 8.1.1

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy on-prem-enterprise-server || rpm -q on-prem-enterprise-server || on-prem-enterprise-server --version

2. UPGRADE to 8.1.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade on-prem-enterprise-server

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade on-prem-enterprise-server

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-11420?

on-prem enterprise server: upgrade to 8.1.1. Exact commands for each OS are on this page.

Is CVE-2026-11420 being exploited?

CVE-2026-11420 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-11420 affect?

CVE-2026-11420 affects on-prem enterprise server. Severity is critical (CVSS 9.8). Two path traversal vulnerabilities in the Network Installation Service (NIS) of Altium Enterprise Server allow an unauthenticated network attacker to write arbitrary files to any writable location on the server filesystem and to read packag

How urgent is CVE-2026-11420?

Priority 53/100. Critical severity; Remotely exploitable, no login, no user action

Related CVEs

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CVE-2026-11419 HIGH 8.8 UPGRADE A path traversal vulnerability exists in the Altium Enterprise Server Vault Service UploadController due to im

References

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