CVE-2026-4881: In affected versions of Octopus Server, permissions were not checked correctly resulting in any authenticated

Routine

MEDIUM 6.5UPGRADE

CVE-2026-4881 is a medium-severity flaw (CVSS 6.5) affecting octopus server. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

In affected versions of Octopus Server, permissions were not checked correctly resulting in any authenticated user being able to make server level changes using a certain API endpoint despite receiving an error.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.2% (top 89%)
CISA exploited list	No
Weakness	CWE-862
Published	2026-06-04
Last modified	2026-07-22

Publisher (CNA): Octopus Deploy · Vendor: octopus

Last updated 2026-07-22 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-06-04 10:16 UTCPublished CVE record published
2026-07-22 20:10 UTCUpdated Record last modified

octopus octopus server UPGRADE

Affected: >= 2023.1.4189 and < 2025.4.10545 · >= 2026.1.675 and < 2026.1.11313

Fixed in: 2025.4.10545, 2026.1.11313

Safe to downgrade to: a release before 2023.1.4189

1. Check installed version

apt-cache policy octopus-server || rpm -q octopus-server || octopus-server --version

2. UPGRADE to 2025.4.10545 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade octopus-server

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade octopus-server

Note

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

3. If no update is available yet, DOWNGRADE to a release before 2023.1.4189 (Debian / Ubuntu)

apt-cache madison octopus-server sudo apt install octopus-server=<VERSION_BEFORE_2023.1.4189> sudo apt-mark hold octopus-server

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list octopus-server sudo dnf downgrade octopus-server-<VERSION_BEFORE_2023.1.4189> sudo dnf versionlock add octopus-server

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

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-2026-4881?

octopus server: upgrade to 2025.4.10545, 2026.1.11313. Exact commands for each OS are on this page.

Is CVE-2026-4881 being exploited?

CVE-2026-4881 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-2026-4881 affect?

CVE-2026-4881 affects octopus server. Severity is medium (CVSS 6.5). In affected versions of Octopus Server, permissions were not checked correctly resulting in any authenticated user being able to make server level changes using a certain API endpoint despite receiving an error.

How urgent is CVE-2026-4881?

Priority 26/100. No elevated risk signals yet.

Related CVEs

CVE-2026-12702 MEDIUM 4.9 UPGRADE In affected versions of Octopus Deploy Insufficient checks on the project trigger actions allows an unauthoriz
CVE-2026-14163 HIGH 7.5 UPGRADE In affected versions of Octopus Server under certain circumstances it is possible for sensitive variables to b

References

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