CVE-2026-48818: Starlette: SSRF and NTLM credential theft via UNC paths in StaticFiles on Windows
Noroxi assessment
Priority: Monitor (action score 30/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 0.64% (FIRST EPSS); higher than 50.4% of all records.
- Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
- According to CISA the attack is automatable: targets can be found by mass scanning.
- Fixed version: Kludex starlette 1.1.0.
Low priority for now. Upgrade to Kludex starlette 1.1.0 or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
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.
- Published
- Jun 17, 2026
- Updated
- Aug 4, 2026
- EPSS
- 0.6% · 50th percentile
- CWE
- CWE-918
Report tools
Action score
30
Monitor
Low priority for now.
- CVSS
- 30 / 40 · 7.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.6%
CISA SSVC decision
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · GitHub_M
- 7.5
- NVD has not scored this yet; the score shown is the CNA’s.
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
Running WordPress? Scan your site free with WP Lens
Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| encode | starlette | cpe:2.3:a:encode:starlette |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- encode starlettebefore 1.1.0
Versions reported by the vendor
Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.
Kludex starlette
- < 1.1.0affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| openSUSE:Tumbleweed | python-graphifyy | before 0.9.48-1.1 | 0.9.48-1.1 |
| PyPI | starlette | before 1.1.0 | 1.1.0 |
Same product
encode: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-48710Starlette has missing Host header validation that poisons request.url.path, bypassing path-based security checksKEV60This week
- CVE-2024-47874Starlette Denial of service (DoS) via multipart/form-data34Monitor
- CVE-2023-29159Directory traversal vulnerability in Starlette versions 0.13.5 and later and prior to 0.27.0 allows a remote unauthenticated attacker to vie31Monitor
Published before and after this one in the same product
- ← EarlierCVE-2023-30798Apr 21, 2023 · MultipartParser DOS with too many fields or files in Starlette Framework30Monitor
- ← EarlierCVE-2025-54121Jul 21, 2025 · Starlette has possible denial-of-service vector when parsing large files in multipart forms21Monitor
- Later →CVE-2026-48817Jun 17, 2026 · Starlette: Arbitrary HTTP method dispatched to `HTTPEndpoint` attributes via `getattr`21Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Kludex starlette | 1.1.0 · description | Vendor (CNA) |
| opensuse:python-graphifyy | 0.9.48-1.1 · openSUSE:Tumbleweed | Package registry (OSV) |
| PyPI:starlette | 1.1.0 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- high · data can be read
- Integrity
- none
- Availability
- none
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- None
- Availability impact
- None
Weakness class (CWE)
CWE-918 · Server-Side Request Forgery (SSRF)CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
ATT&CK techniques
—
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (10 more)Show less
- github.com/Kludex/starlette/pull/3287
- github.com/Kludex/starlette/releases/tag/1.1.0
- github.com/Kludex/starlette/security/advisories/GHSA-wqp7-x3pw-xc5r
- github.com/pypa/advisory-database/tree/main/vulns/starlette/PYSEC-2026-2281.yaml
- access.redhat.com/errata/RHSA-2026:30087
- access.redhat.com/errata/RHSA-2026:30088
- access.redhat.com/errata/RHSA-2026:30089
- access.redhat.com/security/cve/CVE-2026-48818
- bugzilla.redhat.com/show_bug.cgi?id=2490020
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-48818.json
Vendor advisories and official records. Exploit/PoC links are deliberately left out.