# CVE-2026-49820: Probo has an open redirect bypass via path normalization

> Attackers can bypass redirect validation to send users to malicious sites via crafted URLs, enabling phishing attacks against Probo users.

- **Severity:** Medium 4.7 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N`)
- **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:** 13 Aug 2026
- **Updated:** 14 Aug 2026
- **Also known as:** GHSA-x7qq-m748-8p2c, GO-2026-5861

## What is CVE-2026-49820?

CVE-2026-49820 is a medium-severity vulnerability in getprobo probo, published on 13 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

Probo is a self-hostable governance, risk, and compliance (GRC) platform built for engineering and security teams. Probo's `saferedirect` package validates redirect URLs used across authentication flows (OIDC, SAML, session transfer, OAuth connectors, and trust-center magic links). Prior to version 0.19.3.1, the validator only inspected the second character of relative paths, so a URL like `/../\evil.com` passed validation because the second character is `.`. Go's `http.Redirect` normalizes this path to `/\evil.com` before setting the `Location` header. Browsers can interpret the backslash as a host separator and redirect the user to an external domain (`https://evil.com`), bypassing the intended same-origin restriction. This enables open-redirect phishing: an attacker can craft a `continue` parameter (or embed a malicious URL in a session-transfer token) that appears to originate from a trusted Probo domain but redirects victims elsewhere. This is fixed in `go.probo.inc/probo` 0.193.1 by normalizing relative paths with `path.Clean` before validation, rejecting backslashes (including percent-encoded `%5c`) anywhere in the path, and re-checking the normalized result for protocol-relative and backslash prefixes. Self-hosted deployments should upgrade to probod v0.194.1 or later. SaaS deployments on getprobo.com are patched. No practical workaround is available for self-hosted installations.

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

## Which versions are affected by CVE-2026-49820?

3 open source packages ship an affected version, including go.probo.inc/probo.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `go.probo.inc/probo` | Go | All versions | 0.204.0 |
| `go.probo.inc/probo` | Go | All versions | 0.204.0 |
| `go.probo.inc/probo` | Go | All versions | 0.204.0 |

## How do I fix CVE-2026-49820?

Upgrade go.probo.inc/probo to 0.204.0 or later.

## Is CVE-2026-49820 being exploited?

There is no known exploitation of CVE-2026-49820 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-49820 and fix it if it is affected.

What it is: CVE-2026-49820 is a medium-severity vulnerability in getprobo probo, published on 13 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-2026-49820 in the wild and no public exploit code.

Affected packages and fixed versions:
- go.probo.inc/probo (Go): affected all versions; fixed in 0.204.0
- go.probo.inc/probo (Go): affected all versions; fixed in 0.204.0
- go.probo.inc/probo (Go): affected all versions; fixed in 0.204.0

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-2026-49820/ (Markdown: https://insights.sbomify.com/CVE-2026-49820/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-49820
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-49820
- OSV: https://osv.dev/vulnerability/CVE-2026-49820

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-49820/
Summaries are generated and may contain mistakes; the official description above is the record.