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Vulnerability record · CVE-2021-26556 · published 7 October 2021

CVE-2021-26556: Octopus deploy untrusted search path vulnerability

Octopus · Octopus Deploy

When Octopus Server is installed using a custom folder location, folder ACLs are not set correctly and could lead to an unprivileged user using DLL side-loading to gain privileged access.

7.8 CVSS 3.1 High EPSS 0.26% · top 83.8% CWE-426 · Untrusted search path
7.8CVSS 3.1 base score, v2 4.4
0.26%EPSS exploitation probability, 30 days
NoNot in CISA KEV
2Affected product versions listed by NVD
2References
17 Jun 2026Last modified by NVD

Description

When Octopus Server is installed using a custom folder location, folder ACLs are not set correctly and could lead to an unprivileged user using DLL side-loading to gain privileged access.

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected products

2 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://advisories.octopus.com/adv/2021-01---Local-privilege-escalation-in-Octopus-Server-%28CVE-2021-26556%29.173329618
https://advisories.octopus.com/adv/2021-01---Local-privilege-escalation-in-Octopus-Server-%28CVE-2021-26556%29.173329618

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2022-2572Octopus server improper authentication vulnerabilityIn affected versions of Octopus Server where access is managed by an external authentication provider, it was possible that the API key/keys of a dis…EPSS 0.89%9.8CVE-2022-2778Octopus server vulnerabilityIn affected versions of Octopus Deploy it is possible to bypass rate limiting on login using null bytes.EPSS 0.84%9.8CVE-2018-11320Octopus server sensitive information in log file vulnerabilityIn Octopus Deploy 2018.4.4 through 2018.5.1, Octopus variables that are sourced from the target do not have sensitive values obfuscated in the deploy…EPSS 1.4%9.1CVE-2022-2782Octopus server insufficient session expiration vulnerabilityIn affected versions of Octopus Server it is possible for a session token to be valid indefinitely due to improper validation of the session token pa…EPSS 0.57%8.8CVE-2022-4009Octopus server command injection vulnerabilityIn affected versions of Octopus Deploy it is possible for a user to introduce code via offline package creationEPSS 0.72%8.8CVE-2020-10678Octopus deploy vulnerabilityIn Octopus Deploy before 2020.1.5, for customers running on-premises Active Directory linked to their Octopus server, an authenticated user can lever…EPSS 1.0%8.8CVE-2018-18850Octopus server vulnerabilityIn Octopus Deploy 2018.8.0 through 2018.9.x before 2018.9.1, an authenticated user with permission to modify deployment processes could upload a mali…EPSS 12%8.8CVE-2018-5706Octopus deploy improper privilege management vulnerabilityAn issue was discovered in Octopus Deploy before 4.1.9. Any user with user editing permissions can modify teams to give themselves Administer System …EPSS 1.0%

Source: NIST National Vulnerability Database (record CVE-2021-26556), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.