# CVE-2026-111101: HTTP/1.1 chunked request bodies made of 1-byte chunks amplify memory use in Bandit


- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 26 Oct 2026
- **Updated:** 26 Oct 2026
- **Also known as:** EEF-CVE-2026-111101, GHSA-jwh3-j29h-qfmw, UBUNTU-CVE-2026-111101

## 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 (Allocation of Resources Without Limits or Throttling)

## Which versions are affected by CVE-2026-111101?

1 open source package ship an affected version, including bandit.


| Package | Ecosystem | 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.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-111101 and fix it if it is affected.

What it is: CVE-2026-111101 is a high-severity vulnerability in mtrudel bandit, published on 26 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-111101 in the wild and no public exploit code.

Affected packages and fixed versions:
- bandit (Hex): affected from 0.1.0; fixed in 1.14.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-111101/ (Markdown: https://insights.sbomify.com/CVE-2026-111101/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-111101
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-111101
- OSV: https://osv.dev/vulnerability/CVE-2026-111101

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-111101/
Summaries are generated and may contain mistakes; the official description above is the record.