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NVD / CVE Program· CNA GitHub_M

CVE-2026-54282: Starlette: Unvalidated request path concatenated into authority poisons request.url.hostname

Noroxi assessment

Priority: Monitor (action score 21/100)

  • 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: 0.27% (FIRST EPSS).
  • 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.
  • Fixed version: Kludex starlette 1.3.0.

Low priority for now. Upgrade to Kludex starlette 1.3.0 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. Prior to 1.3.0, the HTTP request path is not validated before being used to reconstruct request.url. Because request.url is rebuilt by concatenating {scheme}://{host}{path} and re-parsing the result, a path that does not begin with / (for example @google.com) moves the authority boundary during re-parsing, so request.url.hostname and request.url.netloc become attacker-controlled. Code that reads request.url.hostname (rather than the Host header or scope) can therefore be misled into trusting an attacker-supplied host. This vulnerability is fixed in 1.3.0.

MediumCVSS 5.3 · v3.1—No exploit Fix available
Published
Jun 22, 2026
Updated
Oct 25, 2026
EPSS
0.2% · 19th percentile

Report tools

JSON

Action score

21

Monitor

Low priority for now.

CVSS
21 / 40 · 5.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
5.3
CNA · GitHub_M
3.7
1.6 point gap

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

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.

Follow CVE-2026-54282

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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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.

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Affected 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.

VendorProduct
encodestarlette

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • encode starlettebefore 1.3.0

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

    • < 1.3.0affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12starlettebefore 0.26.1-1+deb12u20.26.1-1+deb12u2
Debian:13starlettebefore 0.46.1-3+deb13u30.46.1-3+deb13u3
Debian:14starlettebefore 1.3.1-11.3.1-1
openSUSE:Leap 16.0python-starlettebefore 0.41.3-160000.4.10.41.3-160000.4.1
openSUSE:Tumbleweedpython-starlettebefore 1.3.1-1.11.3.1-1.1
PyPIstarlettebefore 1.3.01.3.0
SUSE:Linux Enterprise Server 16.0python-starlettebefore 0.41.3-160000.4.10.41.3-160000.4.1

Same product

encode: all records

Other 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 checksKEV
    77This week
  • CVE-2024-47874Starlette Denial of service (DoS) via multipart/form-data
    34Monitor
  • 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 vie
    31Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-48818Jun 17, 2026 · Starlette: SSRF and NTLM credential theft via UNC paths in StaticFiles on Windows
    30Monitor
  • ← EarlierCVE-2026-48817Jun 17, 2026 · Starlette: Arbitrary HTTP method dispatched to `HTTPEndpoint` attributes via `getattr`
    21Monitor
  • Later →CVE-2026-54283Jun 22, 2026 · Starlette: request.form() limits silently ignored for application/x-www-form-urlencoded enable DoS
    30Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Kludex starlette1.3.0 · descriptionVendor (CNA)
debian:starlette0.26.1-1+deb12u2 · Debian:12Package registry (OSV)
opensuse:python-starlette1.3.1-1.1 · openSUSE:TumbleweedPackage registry (OSV)
PyPI:starlette1.3.0Package registry (OSV)
suse:python-starlette0.41.3-160000.4.1 · SUSE:Linux Enterprise Server 16.0Package 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.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, 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
none
Integrity
low · data or configuration can be modified
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
Low
Availability impact
None

Weakness class (CWE)

CWE-706 · Use of Incorrectly-Resolved Name or Reference

CVSS vector

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

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records