Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') vulnerability in…

Why it is Yellow

• CVSS 6.3 medium

References

• https://cna.erlef.org/cves/CVE-2026-114216.html
• https://github.com/mtrudel/bandit/commit/220b9dfd27f9a21305be2afc75cbe585ddc24e7a
• https://github.com/mtrudel/bandit/commit/c31e9e3c76dcbfc239a96eabed5341ced7885ae5
• https://github.com/mtrudel/bandit/security/advisories/GHSA-w5wc-g2hc-g7m2
• https://osv.dev/vulnerability/EEF-CVE-2026-114216

Original description

Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') vulnerability in the HTTP/1.1 chunked body reader of mtrudel bandit allows an unauthenticated remote attacker to smuggle a second request past a front-end proxy via a chunk extension that contains a bare LF. The chunked reader in lib/bandit/http1/socket.ex takes the chunk-size line to be everything up to the first CRLF and discards everything after ; without checking it against the RFC 9112 chunk-ext grammar, so bare LF, bare CR and other control bytes pass. A proxy that ends the size line at a bare LF reads 2;\nxx\r\n40\r\n... as one request whose second chunk holds a GET /admin, while Bandit ends the body early and dispatches GET /admin as a separate pipelined request. Deployments without such a proxy in front of Bandit are not affected. This issue affects bandit: from 1.12.4 before 1.14.0.