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CVE-2026-48818

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

Published: Jun 17, 2026Updated: Aug 4, 2026 Sources: CVE List NVDCWE-918
7.5HIGH
NVD MITRE
EPSS Score
0.4%
Top 70.1%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available
Self-Check
OpenVAS

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:HI:NA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:NIntegrity
None
A:NAvailability
None
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Weaknesses

CWE-918

Affected Products

Kludex
oss-project
starletteLibrary
OSS Libraries / pypi
encode
oss-project
starletteLibrary
OSS Libraries

Exploitability

Official Patch Available
Workaround Available
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Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

2 techniques
Command and Control
Initial Access
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References

https://github.com/Kludex/starlette/security/advisories/GHSA-wqp7-x3pw-xc5r
github.com
https://github.com/Kludex/starlette/pull/3287
github.com
https://github.com/Kludex/starlette/commit/fd53168a7767b6b55ba5af787fd88f49e33cabc5
github.com
and 8 more references View all →

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