mtrudel bandit up to 1.13.9 HTTP/1.1 Chunked Body Reader socket.ex IO.iodata_to_binary allocation of resources

Summaryinfo

A vulnerability, which was classified as problematic, was found in mtrudel bandit up to 1.13.9. Affected is the function IO.iodata_to_binary of the file lib/bandit/http1/socket.ex of the component HTTP1.1 Chunked Body Reader. The manipulation results in allocation of resources. This vulnerability is cataloged as CVE-2026-111101. The attack may be launched remotely. There is no exploit available.

Detailsinfo

A vulnerability, which was classified as problematic, was found in mtrudel bandit up to 1.13.9. Affected is the function IO.iodata_to_binary of the file lib/bandit/http1/socket.ex of the component HTTP1.1 Chunked Body Reader. The manipulation with an unknown input leads to a allocation of resources vulnerability. CWE is classifying the issue as CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. This is going to have an impact on availability. CVE summarizes:

Allocation of Resources Without Limits or Throttling vulnerability in the HTTP/1.1 chunked body reader of mtrudel bandit allows an unauthenticated remote attacker to exhaust server memory and CPU via a request body made of many 1-byte chunks. The chunked reader in lib/bandit/http1/socket.ex keeps every chunk as its own list cell and binary term until IO.iodata_to_binary/1 joins them, and nothing limits the number of chunks. The :length option of read_body/2 counts only data bytes, so tiny chunks cost far more memory than their payload: 48 MB of 1-byte chunks grew one handler process to about 500 MB and took about 6 s of CPU. The route does not need to read the body, because on keep-alive connections ensure_completed/1 drains unread bodies through the same reader. This issue affects bandit: from 0.1.0 before 1.14.0.

The advisory is available at github.com. This vulnerability is traded as CVE-2026-111101 since 10/23/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. Technical details are known, but there is no available exploit. This vulnerability is assigned to T1499 by the MITRE ATT&CK project.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Vendor

• mtrudel

Name

• bandit

Version

• 1.13.0
• 1.13.1
• 1.13.2
• 1.13.3
• 1.13.4
• 1.13.5
• 1.13.6
• 1.13.7
• 1.13.8
• 1.13.9

Website

• Product: https://github.com/mtrudel/bandit/

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