EEF-CVE-2026-39807
- Source
- https://cna.erlef.org/osv/EEF-CVE-2026-39807.html
- Import Source
- https://cna.erlef.org/osv/EEF-CVE-2026-39807.json
- JSON Data
- https://api.osv.dev/v1/vulns/EEF-CVE-2026-39807
- Aliases
-
- CVE-2026-39807
- GHSA-375f-4r2h-f99j
- Published
- 2026-05-01T20:34:22.832Z
- Modified
- 2026-05-02T04:17:33.243Z
- Severity
-
- 6.3 (Medium) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N CVSS Calculator
- Summary
- Client-supplied URI scheme trusted without transport verification in bandit
- Details
-
Summary
Reliance on Untrusted Inputs in a Security Decision vulnerability in mtrudel bandit allows unauthenticated transport-state spoofing on plaintext HTTP connections.
'Elixir.Bandit.Pipeline':determine_scheme/2 in lib/bandit/pipeline.ex returns the client-supplied URI scheme verbatim, ignoring the transport's secure? flag. HTTP/1.1 absolute-form request targets (e.g. GET https://victim/path HTTP/1.1) and the HTTP/2 :scheme pseudo-header are both attacker-controlled strings that flow through this function. Over a plaintext TCP connection, a client can declare https and Bandit will set conn.scheme = :https even though no TLS was negotiated.
Downstream Plug consumers that branch on conn.scheme are silently misled: Plug.SSL's already-secure branch skips its HTTP→HTTPS redirect, cookies emitted with secure: true are sent over plaintext, audit logs record requests as having arrived over HTTPS, and CSRF/SameSite gating may make incorrect decisions.
This issue affects bandit: from 1.0.0 before 1.11.0.
Configuration
The vulnerable system must be accepting plaintext (non-TLS) HTTP connections, either directly or via h2c. Deployments that exclusively use TLS are not affected.
- Database specific
{ "cpe_ids": [ "cpe:2.3:a:mtrudel:bandit:*:*:*:*:*:*:*:*" ], "capec_ids": [ "CAPEC-220" ], "cwe_ids": [ "CWE-807" ] }- References
- Credits
-
-
- Peter Ullrich - FINDER
-
- Mat Trudel - REMEDIATION_DEVELOPER
-
- Jonatan Männchen - ANALYST
-
Affected packages
Hex / bandit
Package
- Name
- bandit
- Purl
- pkg:hex/bandit