CVE-2026-49820

MEDIUMCVSS 4.7/10EPSS 0.29%

Last modified

CVE-2026-49820 is a medium-severity vulnerability rated 4.7/10 on the CVSS scale. 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). EPSS estimates a 0.29% chance of exploitation in the next 30 days.

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.

Metrics

EPSS Probability
0.29%

21.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
getproboprobo< 0.193.1

References

Timeline

Published
Last Modified
Status
Deferred

Frequently Asked Questions

What is CVE-2026-49820?
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.
How severe is CVE-2026-49820?
CVE-2026-49820 has a CVSS score of 4.7/10 (MEDIUM severity). The EPSS model estimates a 0.29% probability of exploitation in the next 30 days.
How do I fix CVE-2026-49820?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST