'Elixir.Bandit.Headers':get_content_length/1 in lib/bandit/headers.ex uses List.keyfind/3, which returns only the first matching header. When a request contains two Content-Length headers with different values, Bandit silently accepts it, uses the first value to read the body, and dispatches the remaining bytes as a second pipelined request on the same keep-alive connection. RFC 9112 §6.3 requires recipients to treat this as an unrecoverable framing error.
When Bandit sits behind a proxy that picks the last Content-Length value and forwards the request rather than rejecting it, an unauthenticated attacker can smuggle requests past edge WAF rules, path-based ACLs, rate limiting, and audit logging.
This issue affects bandit: before 1.11.0.
No advisories yet.
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
Sat, 02 May 2026 02:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
|
Fri, 01 May 2026 21:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | Inconsistent Interpretation of HTTP Requests vulnerability in mtrudel bandit allows HTTP request smuggling via duplicate Content-Length headers. 'Elixir.Bandit.Headers':get_content_length/1 in lib/bandit/headers.ex uses List.keyfind/3, which returns only the first matching header. When a request contains two Content-Length headers with different values, Bandit silently accepts it, uses the first value to read the body, and dispatches the remaining bytes as a second pipelined request on the same keep-alive connection. RFC 9112 §6.3 requires recipients to treat this as an unrecoverable framing error. When Bandit sits behind a proxy that picks the last Content-Length value and forwards the request rather than rejecting it, an unauthenticated attacker can smuggle requests past edge WAF rules, path-based ACLs, rate limiting, and audit logging. This issue affects bandit: before 1.11.0. | |
| Title | CL.CL HTTP request smuggling via duplicate Content-Length in bandit | |
| First Time appeared |
Mtrudel
Mtrudel bandit |
|
| Weaknesses | CWE-444 | |
| CPEs | cpe:2.3:a:mtrudel:bandit:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Mtrudel
Mtrudel bandit |
|
| References |
| |
| Metrics |
cvssV4_0
|
Projects
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Status: PUBLISHED
Assigner: EEF
Published:
Updated: 2026-05-02T04:17:41.202Z
Reserved: 2026-04-07T12:28:54.916Z
Link: CVE-2026-39805
Updated: 2026-05-02T01:21:06.449Z
Status : Received
Published: 2026-05-01T21:16:17.037
Modified: 2026-05-02T02:16:00.180
Link: CVE-2026-39805
No data.
OpenCVE Enrichment
Updated: 2026-05-02T10:15:16Z