Vulnerability · Published Oct 26, 2026 · Assigned by EEF

CVE-2026-114216Chunk extensions accept bare LF and CR, enabling request smuggling in Bandit

Medium 6.3

In plain English

A medium-severity security flaw in bandit from mtrudel. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 49% of all known vulnerabilities).

Severity (CVSS 4.0)6.3Medium

Exploit odds (30 days)0.6%top 51.0% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Ubuntu:22.04:LTS	bandit	no fix listed	UBUNTU-CVE-2026-114216
Ubuntu:24.04:LTS	bandit	no fix listed	UBUNTU-CVE-2026-114216
Ubuntu:26.04:LTS	bandit	no fix listed	UBUNTU-CVE-2026-114216
Ubuntu:26.10	bandit	no fix listed	UBUNTU-CVE-2026-114216

Affected products (as reported)

Vendor	Product	Versions
mtrudel	bandit	1.12.4 – before 1.14.0
mtrudel	bandit	c31e9e3c76dcbfc239a96eabed5341ced7885ae5 – before 220b9dfd27f9a21305be2afc75cbe585ddc24e7a

Weakness: CWE-444 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N

References

Chunk extensions accept bare LF and CR, enabling request smuggling in Bandit vendor-advisory, related
EEF CNA record for CVE-2026-114216 related
OSV record EEF-CVE-2026-114216 related
Introducing commit c31e9e3 in mtrudel/bandit related
Fix commit 220b9df in mtrudel/bandit patch