CVE-2026-48818Starlette: SSRF and NTLM credential theft via UNC paths in StaticFiles on Windows
- 7.5HighCVSS base score
- 0.37%Exploitation in 30 daysEPSS · top 69% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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.
Timeline
ID reserved
By GitHub_M
- 26 days later
· 26 days later
Published
- 48 days later
· 48 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N |
| redhat-SADPADP (enrichment) | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N |
| NVDNVD · Modified | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N |
- EPSS (exploitation in 30 days)
- 0.37% · top 69% of all CVEs (12 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.
Affected products
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- PyPIstarletteGHSA-wqp7-x3pw-xc5r (opens in a new tab)
References
References11
- https://github.com/Kludex/starlette/security/advisories/GHSA-wqp7-x3pw-xc5r (opens in a new tab)x_refsource_CONFIRM
- https://github.com/Kludex/starlette/pull/3287 (opens in a new tab)x_refsource_MISC
- https://github.com/Kludex/starlette/commit/fd53168a7767b6b55ba5af787fd88f49e33cabc5 (opens in a new tab)x_refsource_MISC
- https://github.com/Kludex/starlette/releases/tag/1.1.0 (opens in a new tab)x_refsource_MISC
- https://github.com/pypa/advisory-database/tree/main/vulns/starlette/PYSEC-2026-2281.yaml (opens in a new tab)x_refsource_MISC
- https://access.redhat.com/security/cve/CVE-2026-48818 (opens in a new tab)vdb-entryx_refsource_REDHAT
- RHBZ#2490020 (opens in a new tab)issue-trackingx_refsource_REDHAT
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-48818.json (opens in a new tab)x_sadp-csaf-vex
- https://access.redhat.com/errata/RHSA-2026:30089 (opens in a new tab)vendor-advisoryx_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:30088 (opens in a new tab)vendor-advisoryx_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:30087 (opens in a new tab)vendor-advisoryx_refsource_REDHAT
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-37773 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-wqp7-x3pw-xc5r (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-48818)Record last updated .