CVE-2026-111101 HTTP/1.1 chunked request bodies made of 1-byte chunks amplify memory use in Bandit
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-111101?
CVE-2026-111101 is a high-severity vulnerability in mtrudel bandit, published on 26 Oct 2026.
Official description
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.
Weakness: CWE-770
Which versions are affected by CVE-2026-111101?
1 open source package ship an affected version, including bandit.
| Package | Affected | Fixed in |
|---|---|---|
bandit Hex | From 0.1.0 | 1.14.0 |
How do I fix CVE-2026-111101?
Upgrade bandit to 1.14.0 or later.
Is CVE-2026-111101 being exploited?
There is no known exploitation of CVE-2026-111101 in the wild and no public exploit code.
Sources
Also known as EEF-CVE-2026-111101, GHSA-jwh3-j29h-qfmw, UBUNTU-CVE-2026-111101.