CVE-2026-48818Starlette: SSRF and NTLM credential theft via UNC paths in StaticFiles on Windows
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It affects Kludex starlette and 10 other products. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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
- 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- Weakness (CWE)
- CWE-918
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- GitHub_M
- NVD analysis
- Modified
- Record last updated
- Aug 4, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Kludex starlette kludex:starlette (from the name) | before 1.1.0 | CNA record |
Red Hat Red Hat AI Inference Server 3.3 redhat:ai_inference_server | from 1782352919 not affected | CISA ADP |
Red Hat Exploit Intelligence redhat:exploit_intelligence | 0 | CISA ADP |
Red Hat Migration Toolkit for Applications 8 redhat:migration_toolkit_applications | 8 | CISA ADP |
Red Hat OpenShift Lightspeed redhat:openshift_lightspeed | Versions not stated | CISA ADP |
Red Hat Red Hat Ansible Automation Platform 2 redhat:ansible_automation_platform | 2 | CISA ADP |
Red Hat Red Hat Enterprise Linux AI (RHEL AI) 3 redhat:enterprise_linux_ai | 3 | CISA ADP |
Red Hat Red Hat Hardened Images redhat:hummingbird | 1 | CISA ADP |
Red Hat Red Hat OpenShift AI (RHOAI) redhat:openshift_ai | Versions not stated | CISA ADP |
Red Hat Red Hat Satellite 6 redhat:satellite | 6 | CISA ADP |
encode starlette encode:starlette | before 1.1.0 | NVD |
References
- https://github.com/Kludex/starlette/security/advisories/GHSA-wqp7-x3pw-xc5rx-refsource-confirm, mitigation, vendor-advisory
- https://github.com/Kludex/starlette/pull/3287x-refsource-misc, patch
- https://github.com/Kludex/starlette/commit/fd53168a7767b6b55ba5af787fd88f49e33cabc5x-refsource-misc, patch
- https://github.com/Kludex/starlette/releases/tag/1.1.0x-refsource-misc, release-notes
- https://github.com/pypa/advisory-database/tree/main/vulns/starlette/PYSEC-2026-2281.yamlx-refsource-misc
- https://access.redhat.com/errata/RHSA-2026:30087
- https://access.redhat.com/errata/RHSA-2026:30088
- https://access.redhat.com/errata/RHSA-2026:30089
- 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
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.