Is CVE-2026-100397 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-100397 being exploited in the wild.

How severe is CVE-2026-100397?

Critical severity, with a CVSS score of 9.8, published 13 November 2026.

Which products and versions are affected?

rucio (PyPI) >= 1.14.0.post1, < 35.9.1.

Is there a fix for CVE-2026-100397?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-100397 attacked?

It is attacked over the network, in a hosted service.

Am I affected by CVE-2026-100397?

Check whether you run rucio (PyPI) or Rucio Project Rucio at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-100397: Rucio unauthenticated administrator impersonation in SSH challenge tokens

Q: Is there a fix for CVE-2026-100397?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

Q: How is CVE-2026-100397 attacked?

It is attacked over the network, in a hosted service.

Q: Am I affected by CVE-2026-100397?

Check whether you run rucio (PyPI) or Rucio Project Rucio at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-100397 · Severity: critical · CVSS 9.8 · Published 2026-11-13

Rucio is a data management system used by large research organizations to organize and access massive datasets. The authentication system mistakenly treats temporary SSH challenge tokens as valid credentials, allowing an attacker without a valid account to impersonate any user including administrators. An attacker can obtain a challenge token for a privileged account and use it to access the API with full administrative privileges.

Technologies: rucio (PyPI). Vendors: PyPI.

Quick answers

Is CVE-2026-100397 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-100397 being exploited in the wild.
How severe is CVE-2026-100397?: Critical severity, with a CVSS score of 9.8, published 13 November 2026.
Which products and versions are affected?: rucio (PyPI) >= 1.14.0.post1, < 35.9.1.
Is there a fix for CVE-2026-100397?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-100397 attacked?: It is attacked over the network, in a hosted service.
Am I affected by CVE-2026-100397?: Check whether you run rucio (PyPI) or Rucio Project Rucio at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

The vulnerability exists in the `validate_auth_token` function in `lib/rucio/core/authentication.py`, which does not differentiate between SSH challenge tokens and legitimate authentication tokens stored in the same database table. An unauthenticated attacker can request a challenge token for any account via the REST API without prior authentication, then use the challenge token as a bearer token in the X-Rucio-Auth-Token header to authenticate to other API endpoints. The challenge token is valid for approximately ten seconds, providing a narrow but exploitable window.

Affected products

Rucio Project Rucio

Identifiers

CVE-2026-100397
GHSA-x585-4vv8-2mh2

Timeline

2026-11-13: disclosed

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.