CVE-2026-48817 | Starlette: Arbitrary HTTP method dispatched to `HTTPEndpoint` attributes via `getattr`

Starlette is a lightweight ASGI framework/toolkit. In versions 1.0.1 and below, when dispatching a request, HTTPEndpoint selects the handler by lowercasing the HTTP method and looking it up as an attribute with getattr, without restricting the lookup to a known set of HTTP verbs. When an HTTPEndpoint subclass is registered through Route(...) without an explicit methods= argument, the route does not constrain the method and every method reaches the endpoint. If a non-standard HTTP method whose lowercased name matches an attribute on the endpoint subclass reaches the endpoint, that attribute is invoked as if it were a request handler. An attacker can use this to reach methods that were never meant to be HTTP handlers, such as internal helpers, without the authorization checks applied by the intended public handler. An application (including Starlette-based frameworks like FastAPI) is affected if it registers an HTTPEndpoint subclass via Route(...) without explicitly setting methods=, and that subclass includes extra methods named like non-standard HTTP verbs that take one request argument and return a response. This issue has been fixed in version 1.1.0.

Published: 2026-06-17 Last update: 2026-06-22 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2026-48817 is rated Low Risk (30.8/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.35%). Mandatory action: Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-48817

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-18 0.04% 0.35% +0.31%
2 2026-06-12 0.04%

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-48817

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
3.9 1.4 [email protected]

Weakness enumeration for CVE-2026-48817

GitHub Security Advisory for CVE-2026-48817

GHSA-x746-7m8f-x49c · Severity: medium · Ecosystem: pip — Starlette: Arbitrary HTTP method dispatched to `HTTPEndpoint` attributes via `getattr`

OS Trackers for CVE-2026-48817

vendor priority summary link
debian not yet assigned CVE-2026-48817 not yet assigned priority: Debian including 1 source packages (starlette), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): open 3, resolved 2. https://security-tracker.debian.org/tracker/CVE-2026-48817
redhat medium https://access.redhat.com/security/cve/CVE-2026-48817
suse medium https://www.suse.com/security/cve/CVE-2026-48817/
ubuntu medium CVE-2026-48817 medium priority: Ubuntu including 1 source packages (starlette), 5 status rows across 5 suites (jammy, noble, questing, resolute, upstream): needs-triage 4, released 1. https://ubuntu.com/security/CVE-2026-48817

Affected software / configurations for CVE-2026-48817

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2026-48817

cvelogic Threat Intelligence