CVE-2026-48818
HIGH 7.5Starlette is a lightweight ASGI framework/toolkit. In versions 1.0.1 and earlier, StaticFiles on Windows is vulnerable to SSRF. An UNC path such as \\attacker.com\share can cause os.path.realpath to initiate an outbound SMB connection before the path is rejected, exposing the service account’s NTLMv2 credentials for offline cracking or relay even though the HTTP response is only a 404. The issue affects default follow_symlink=False deployments, including frameworks built on Starlette such as FastAPI; POSIX systems and follow_symlink=True are unaffected. The issue is fixed in 1.1.0.
Severe if exploited (CVSS 7.5), but no known exploitation and low modeled probability. Patch on a normal cadence.
Exploitation likelihood
0.4%chance of exploitation in 30 days · 29th percentile
Impact if exploited
7.5CVSS 3.1 · HIGH
- ConfidentialityHigh
- IntegrityNone
- AvailabilityNone
What an attacker needs
- ✓Access: Reachable over the network — no local access needed
- ✓Privileges: No account or privileges required
- ✓User interaction: No user interaction needed
- ✓Complexity: No special conditions — reliably repeatable
✓ lowers the bar for an attacker · ⚠ raises it
Affected
Products Starlette Red Hat Ai Inference Server 3.3 Exploit Intelligence Migration Toolkit For Applications 8 Openshift Lightspeed Red Hat Ai Inference Server Red Hat Ansible Automation Platform 2 Red Hat Enterprise Linux Ai (Rhel Ai) 3
Weakness (CWE)
- CWE-918: Server-side request forgery (SSRF)
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
References
Advisories
Technical & other
- https://github.com/Kludex/starlette/security/advisories/GHSA-wqp7-x3pw-xc5r
- https://github.com/Kludex/starlette/pull/3287
- https://github.com/Kludex/starlette/commit/fd53168a7767b6b55ba5af787fd88f49e33cabc5
- https://github.com/Kludex/starlette/releases/tag/1.1.0
- https://access.redhat.com/security/cve/CVE-2026-48818
- https://bugzilla.redhat.com/show_bug.cgi?id=2490020
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-48818.json