mediumCVSS 4.7Vulnerability

CVE-2026-49820

### Impact Probo's `saferedirect` package validates redirect URLs used across authentication flows (OIDC, SAML, session transfer, OAuth connectors, and trust-center magic links). 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. ### Patches Fixed in `go.probo.inc/probo` 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. ### Workarounds No practical workaround for self-hosted installations. Upgrade to the patched release.

Properties

severity
medium
summary
Probo has an open redirect bypass via path normalization
epss_score
0.00291
cvss_score
4.7
ghsa_published
2026-06-30T18:31:50Z
source_url
https://github.com/advisories/GHSA-x7qq-m748-8p2c
ghsa_updated
2026-06-30T18:31:51Z
ghsa_id
GHSA-x7qq-m748-8p2c
cve_id
CVE-2026-49820
cvss_vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N
is_ghsa_only
false
epss_percentile
0.2148

Related Entities (5)

ENRICHED_BY (1)

[Source]FIRST EPSS

REPORTED_BY (1)

[Source]GitHub Advisory Database

VULNERABLE_TO (1)

[Software]go/go.probo.inc/probo

AFFECTS (1)

[Software]go/go.probo.inc/probo

HAS_WEAKNESS (1)

[Weakness]URL Redirection to Untrusted Site ('Open Redirect')

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CVE-2026-49820 (CVSS 4.7) — Ninja Signal Threat Intelligence | Ninja Signal