CVE-2026-48818 — HIGH (7.5)

Q: How severe is CVE-2026-48818?

CVE-2026-48818 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.

Q: Is there a patch for CVE-2026-48818?

Check the references section above for vendor advisories and patch information. Affected products include: Encode Starlette.

Vulnerability 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.

CVSS Score

7.5

HIGH

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

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality

HIGH

Integrity

NONE

Availability

NONE

Affected Products

Vendor	Product	Versions
Encode	Starlette	< 1.1.0

Related Weaknesses (CWE)

CWE-918

References

FAQ

What is CVE-2026-48818?

CVE-2026-48818 is a vulnerability with a CVSS score of 7.5 (HIGH). 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 i...

How severe is CVE-2026-48818?

CVE-2026-48818 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-48818?

Check the references section above for vendor advisories and patch information. Affected products include: Encode Starlette.