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CVE-2026-40961 Apache Software Foundation CVE debrief

A URL redirection vulnerability in Apache Airflow's login redirect route allows authenticated users to craft URLs that bypass the `is_safe_url` validation, enabling open redirect attacks from a trusted Airflow domain to attacker-controlled origins. The flaw resides in insufficient validation of the `next=` query parameter during login flow redirection. Apache has addressed this in version 3.2.2. The vulnerability was published to the NVD on June 1, 2026, with a fix pull request and security discussion available via official Apache channels.

Vendor
Apache Software Foundation
Product
Apache Airflow
CVSS
HIGH 7.2
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-01
Original CVE updated
2026-07-21
Advisory published
2026-06-01
Advisory updated
2026-07-21

Who should care

Organizations running Apache Airflow versions prior to 3.2.2, particularly those with internet-facing or multi-tenant deployments where authenticated users could leverage redirects for phishing or credential harvesting against other users.

Technical summary

The vulnerability exists in Apache Airflow's login redirect route where the `is_safe_url` check can be bypassed through crafted URLs, allowing authenticated users to redirect from a trusted Airflow instance to arbitrary external domains. This is classified as CWE-601 (URL Redirection to Untrusted Site). The attack requires an authenticated session and leverages the `next=` query parameter commonly used in login flows. The vendor fix in apache-airflow 3.2.2 corrects the URL validation logic. A compensating control involves reverse proxy filtering of the `next=` parameter to prevent off-domain redirection requests from reaching the application.

Defensive priority

medium

Recommended defensive actions

  • Upgrade apache-airflow to version 3.2.2 or later to obtain the vendor fix for the login redirect validation flaw.
  • As a defense-in-depth measure, deploy Airflow behind a reverse proxy configured to strip or validate off-domain `next=` query parameters before they reach the login endpoint.
  • Review access logs for anomalous `next=` parameter values in requests to the login redirect route to identify potential exploitation attempts.
  • Verify that any custom authentication integrations or login handlers do not independently reintroduce open redirect behavior through similar `next` parameter handling.

Evidence notes

The NVD record lists CWE-601 (URL Redirection to Untrusted Site, 'Open Redirect') as the primary weakness. The fix is tracked via GitHub pull request 65557, and an Apache security mailing list thread documents coordinated disclosure.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-40961 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-40961

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-40961 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-40961

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.