CVE-2018-15798 is a medium-severity (CVSS 5.4) Open Redirect vulnerability in github.com/concourse/concourse. A fix is available for github.com/concourse/concourse — see the affected versions and patch details below.
Pivotal Concourse Open Redirect in Login Flow
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
github.com/concourse/concourse🐹github.com/concourse/concourse🐹github.com/concourse/concourseReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Pivotal Concourse Release, versions 4.x prior to 4.2.2, login flow allows redirects to untrusted websites. A remote unauthenticated attacker could convince a user to click on a link using the oAuth redirect link with an untrusted website and gain access to that user's access token in Concourse.
Specific Go Packages Affected
github.com/concourse/concourse/skymarshal/skyserver
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/concourse/concourse | all versions | 5.2.8go get github.com/concourse/concourse@v5.2.8 |
| 🐹Go | github.com/concourse/concourse | ≥ 5.3.0&&< 5.5.10 | 5.5.10go get github.com/concourse/concourse@v5.5.10 |
| 🐹Go | github.com/concourse/concourse | ≥ 5.6.0&&< 5.8.1 | 5.8.1go get github.com/concourse/concourse@v5.8.1 |
Affected Products
concoursepivotal_softwareDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/concourse/concourse, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/concourse/concourse to 5.2.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2018-15798 is resolved across your whole dependency graph.
Workarounds
Stop reflecting attacker-controlled destinations: resolve every redirect target against an allowlist of paths or hosts you own, prefer a server-side key over a full URL in the request, and reject absolute URLs entirely where the flow only ever needs a relative one.
Frequently Asked Questions
Is CVE-2018-15798 in your dependencies?
Find it across Go, including transitive dependencies.