# CVE-2026-49826: Concourse login flow has an open redirect issue

> Attackers can craft URLs to redirect users from Concourse to malicious sites, facilitating phishing attacks to steal credentials.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 14 Aug 2026
- **Updated:** 14 Aug 2026
- **Also known as:** BIT-concourse-2026-49826, GHSA-8w27-c4vc-88q9, GO-2026-5866

## What is CVE-2026-49826?

CVE-2026-49826 is a vulnerability in concourse, published on 14 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

Concourse is a container-based automation system written in Go. Prior to version 8.2.3, an attacker is able to craft and send a user a URL that will redirect the user from the Concourse web server to any other site. This could be used in a phishing attack to steal user's credentials. This has been fixed in 8.2.3. No known workarounds are available.

Weakness: CWE-601 (URL Redirection to Untrusted Site)

## Which versions are affected by CVE-2026-49826?

4 open source packages ship an affected version, including github.com/concourse/concourse and concourse.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/concourse/concourse` | Go | All versions | 1.6.1-0.20260526150512-ac60be5f0435 |
| `github.com/concourse/concourse` | Go | All versions | 1.6.1-0.20260526150512-ac60be5f0435 |
| `github.com/concourse/concourse` | Go | All versions | 1.6.1-0.20260526150512-ac60be5f0435 |
| `concourse` | Bitnami | All versions | 8.2.3 |

## How do I fix CVE-2026-49826?

Upgrade github.com/concourse/concourse to 1.6.1-0.20260526150512-ac60be5f0435 or later.

## Is CVE-2026-49826 being exploited?

There is no known exploitation of CVE-2026-49826 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-49826 and fix it if it is affected.

What it is: CVE-2026-49826 is a vulnerability in concourse, published on 14 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-49826 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/concourse/concourse (Go): affected all versions; fixed in 1.6.1-0.20260526150512-ac60be5f0435
- github.com/concourse/concourse (Go): affected all versions; fixed in 1.6.1-0.20260526150512-ac60be5f0435
- github.com/concourse/concourse (Go): affected all versions; fixed in 1.6.1-0.20260526150512-ac60be5f0435
- concourse (Bitnami): affected all versions; fixed in 8.2.3

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-49826/ (Markdown: https://insights.sbomify.com/CVE-2026-49826/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-49826
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-49826
- OSV: https://osv.dev/vulnerability/CVE-2026-49826

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-49826/
Summaries are generated and may contain mistakes; the official description above is the record.