CVE-2026-48818
Starlette: SSRF and NTLM credential theft via UNC paths in StaticFiles on Windows
Description
Starlette 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.
INFO
Published Date :
June 17, 2026, 7:18 p.m.
Last Modified :
June 30, 2026, 3:20 a.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 3.1 | HIGH | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c |
Solution
- Update Starlette to version 1.1.0 or later.
- Configure follow_symlink=True if updating is not possible.
- Restrict network access for the service account.
- Monitor for suspicious outbound SMB connections.
Public PoC/Exploit Available at Github
CVE-2026-48818 has a 5 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-48818.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-48818 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-48818
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
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a lightweight Platform-as-a-Service (PaaS) that allows developers to deploy applications by simply pushing their code. It automatically builds, deploys, and exposes applications via a public URL.
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Python
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-48818 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-48818 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Modified by 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Jun. 30, 2026
Action Type Old Value New Value Added Affected [{'cpes': ['cpe:/a:redhat:ai_inference_server:3.3::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat AI Inference Server 3.3', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:exploit_intelligence:0'], 'vendor': 'Red Hat', 'product': 'Exploit Intelligence', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:migration_toolkit_applications:8'], 'vendor': 'Red Hat', 'product': 'Migration Toolkit for Applications 8', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:openshift_lightspeed'], 'vendor': 'Red Hat', 'product': 'OpenShift Lightspeed', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:ai_inference_server:3'], 'vendor': 'Red Hat', 'product': 'Red Hat AI Inference Server', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:ansible_automation_platform:2'], 'vendor': 'Red Hat', 'product': 'Red Hat Ansible Automation Platform 2', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:enterprise_linux_ai:3'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux AI (RHEL AI) 3', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:hummingbird:1'], 'vendor': 'Red Hat', 'product': 'Red Hat Hardened Images', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:openshift_ai'], 'vendor': 'Red Hat', 'product': 'Red Hat OpenShift AI (RHOAI)', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:satellite:6'], 'vendor': 'Red Hat', 'product': 'Red Hat Satellite 6', 'defaultStatus': 'unaffected'}] Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N Added CWE CWE-918 Added Reference https://access.redhat.com/errata/RHSA-2026:30087 Added Reference https://access.redhat.com/errata/RHSA-2026:30088 Added Reference https://access.redhat.com/errata/RHSA-2026:30089 Added Reference https://access.redhat.com/security/cve/CVE-2026-48818 Added Reference https://bugzilla.redhat.com/show_bug.cgi?id=2490020 Added Reference https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-48818.json -
Initial Analysis by [email protected]
Jun. 26, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:encode:starlette:*:*:*:*:*:python:*:* versions up to (excluding) 1.1.0 Added Reference Type GitHub, Inc.: https://github.com/Kludex/starlette/commit/fd53168a7767b6b55ba5af787fd88f49e33cabc5 Types: Patch Added Reference Type GitHub, Inc.: https://github.com/Kludex/starlette/pull/3287 Types: Patch Added Reference Type GitHub, Inc.: https://github.com/Kludex/starlette/releases/tag/1.1.0 Types: Release Notes Added Reference Type GitHub, Inc.: https://github.com/Kludex/starlette/security/advisories/GHSA-wqp7-x3pw-xc5r Types: Mitigation, Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 17, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-48818', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'yes'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-06-17T19:31:32.312592Z'} -
New CVE Received by [email protected]
Jun. 17, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'Kludex', 'product': 'starlette', 'versions': [{'status': 'affected', 'version': '< 1.1.0'}]}] Added Description Starlette 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. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N Added CWE CWE-918 Added Reference https://github.com/Kludex/starlette/commit/fd53168a7767b6b55ba5af787fd88f49e33cabc5 Added Reference https://github.com/Kludex/starlette/pull/3287 Added Reference https://github.com/Kludex/starlette/releases/tag/1.1.0 Added Reference https://github.com/Kludex/starlette/security/advisories/GHSA-wqp7-x3pw-xc5r