CVE-2026-128637

Description

The MISP Modules website component contains an open redirect vulnerability in its login endpoint. The /login route accepted a user-supplied next query parameter and passed it directly to Flask's redirect() function without validating the destination. An attacker could craft a URL such as https://victim-host/login?next=https://attacker.example/phish and deliver it to a user (e.g., via email or a lookalike page). After the user successfully authenticated, the application issued a 302 redirect to the attacker-controlled external URL. This enables phishing attacks where a user, believing they are still on the legitimate MISP Modules site, may enter additional credentials or sensitive information on the attacker's page. It can also be used to obscure the true destination of a link, bypassing user trust in the legitimate domain. The vulnerability requires the victim to interact with the crafted URL and complete a login, but no prior authentication or special configuration is needed on the attacker's side. The affected component is the website sub-project of misp-modules, specifically the account blueprint in website/app/account/account.py. No version boundaries are specified in the patch metadata.

Severity scores

Each score is shown as its source gave it. They are not averaged or merged.

• 5.1CVSS 4.0, Mediumfrom the CNA (CIRCL)CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:N/SA:N

What to do

• The fix introduces a _safe_next_url() validation function that restricts post-login redirect destinations to local paths or same-host HTTP(S) URLs. Any target that is empty, contains backslashes, control characters, leading/trailing whitespace, an unrecognized scheme, a mismatched host, or a protocol-relative form is rejected and the user is redirected to the home page (/). Accepted same-host URLs are normalized to local paths (scheme and authority stripped) while preserving query strings and fragments, ensuring the Location header always contains a relative path. This eliminates the ability to redirect users to arbitrary external destinations after authentication.CNA solution statement

Historical context and remediation

This reference retains the original CVE publication date. A recent record update does not mean a new attack occurred.

CAPEC-113 Open Redirect (CNA impact statement)

Version statuses below come from the CNA. An “unaffected” version is not necessarily a currently supported release or proof of a patch date. EPSS is a dated risk estimate, not a count of historical attacks.

Read the original CVE record.

Affected products

Timeline

1. 13 Nov 2026 Published

Weakness

• CWE-601

References

• Security patchpatch