CVE-2021-26556
When Octopus Server is installed using a custom folder location, folder ACLs are not set...
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.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Required
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
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.
- Record
CVE-2021-26556- CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - CVSS 2.0
- 4.4 Medium
AV:L/AC:M/Au:N/C:P/I:P/A:P - Weakness
- CWE-426
- Updated
- 2026-11-02
CVE List No score
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.
- Record
CVE-2021-26556- Updated
- 2026-11-02
EUVDEUVD-2021-13355 No score
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.
- Record
EUVD-2021-13355- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-cpf5-2wrr-hcvc
When Octopus Server is installed using a custom folder location, folder ACLs are not set...
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.
- Record
GHSA-cpf5-2wrr-hcvc- CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - Weakness
- CWE-426
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-26556 is a high vulnerability (CVSS 7.8) in Octopus Server, published October 7, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.26%, the 18th percentile. No source names a fixed version.
References
advisories.octopus.com/adv/2021-01---Local-privilege-escalation-in-Octopus-Server-%28CVE-2021-26556%29.1733296189.html
nvd.nist.gov/vuln/detail/CVE-2021-26556
github.com/advisories/GHSA-cpf5-2wrr-hcvc