What is CVE-2020-26161?

CVE-2020-26161 is a medium-severity vulnerability in Octopus Deploy, classified under URL Redirection to Untrusted Site (Open Redirect). CVSS score: 6.1/10. Published 2020-10-26.

How severe is CVE-2020-26161?

Medium severity. CVSS v3 base score is 6.1 out of 10.

Open Redirect in Octopus Deploy

CVE-2020-26161

In Octopus Deploy through 2020.4.2, an attacker could redirect users to an external site via a modified HTTP Host header.

Vulnerability class: Open Redirect

Published 2020-10-26 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.011 (63.6th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 64th percentile — 63.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.011 · newest: 0.011 · change: 0.000

Affected products

Octopus Deploy

Weakness classification (CWE)

CWE-601 — URL Redirection to Untrusted Site (Open Redirect)

References

github.com/OctopusDeploy (Third Party Advisory)
github.com/OctopusDeploy/Issues/issues/6622 (Third Party Advisory, Issue Tracking)
github.com/OctopusDeploy/Issues/issues/6627 (Third Party Advisory, Issue Tracking)

Frequently asked questions

What is CVE-2020-26161?: CVE-2020-26161 is a medium-severity vulnerability in Octopus Deploy, classified under URL Redirection to Untrusted Site (Open Redirect). CVSS score: 6.1/10. Published 2020-10-26.
How severe is CVE-2020-26161?: Medium severity. CVSS v3 base score is 6.1 out of 10.