Starlette: SSRF and NTLM credential theft via UNC paths in StaticFiles on Windows

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Summary

CVECVE-2026-48818
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-06-17 19:18:09 UTC
Updated2026-06-30 03:20:27 UTC
DescriptionStarlette 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.

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from ADP

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS: 0.003680000 probability, percentile 0.287690000 (date 2026-07-04)

Problem Types: CWE-918 | CWE-918 CWE-918: Server-Side Request Forgery (SSRF) | CWE-918 Server-Side Request Forgery (SSRF)

VersionSourceTypeScoreSeverityVector
3.1ADPCVSS7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
3.1[email protected]Secondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
3.10b0ca135-0b70-47e7-9f44-1890c2a1c46cSecondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
3.1CNADECLARED7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Encode Starlette All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Kludex Starlette affected < 1.1.0 Not specified
ADP Red Hat Red Hat AI Inference Server 3.3 Not specified Not specified
ADP Red Hat Exploit Intelligence Not specified Not specified
ADP Red Hat Migration Toolkit For Applications 8 Not specified Not specified
ADP Red Hat OpenShift Lightspeed Not specified Not specified
ADP Red Hat Red Hat AI Inference Server Not specified Not specified
ADP Red Hat Red Hat Ansible Automation Platform 2 Not specified Not specified
ADP Red Hat Red Hat Enterprise Linux AI RHEL AI 3 Not specified Not specified
ADP Red Hat Red Hat Hardened Images Not specified Not specified
ADP Red Hat Red Hat OpenShift AI RHOAI Not specified Not specified
ADP Red Hat Red Hat Satellite 6 Not specified Not specified

References

ReferenceSourceLinkTags
security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-48818.json 0b0ca135-0b70-47e7-9f44-1890c2a1c46c security.access.redhat.com
access.redhat.com/security/cve/CVE-2026-48818 0b0ca135-0b70-47e7-9f44-1890c2a1c46c access.redhat.com
github.com/Kludex/starlette/pull/3287 [email protected] github.com Patch
access.redhat.com/errata/RHSA-2026:30089 0b0ca135-0b70-47e7-9f44-1890c2a1c46c access.redhat.com
github.com/Kludex/starlette/security/advisories/GHSA-wqp7-x3pw-xc5r [email protected] github.com Mitigation, Vendor Advisory
access.redhat.com/errata/RHSA-2026:30087 0b0ca135-0b70-47e7-9f44-1890c2a1c46c access.redhat.com
access.redhat.com/errata/RHSA-2026:30088 0b0ca135-0b70-47e7-9f44-1890c2a1c46c access.redhat.com
github.com/Kludex/starlette/releases/tag/1.1.0 [email protected] github.com Release Notes
bugzilla.redhat.com/show_bug.cgi 0b0ca135-0b70-47e7-9f44-1890c2a1c46c bugzilla.redhat.com
github.com/Kludex/starlette/commit/fd53168a7767b6b55ba5af787fd88f49e33cabc5 [email protected] github.com Patch
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Additional Advisory Data

SourceTimeEvent
ADP2026-06-17T19:03:44.998ZReported to Red Hat.
ADP2026-06-17T17:50:12.399ZMade public.

Solutions

ADP: RHSA-2026:30089: Red Hat AI Inference Server 3.3

ADP: RHSA-2026:30088: Red Hat AI Inference Server 3.3

ADP: RHSA-2026:30087: Red Hat AI Inference Server 3.3

Workarounds

ADP: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

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