# CVE-2026-113436: Quadratic bignum parsing of Content-Length and Host port values 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-2026-113436, GHSA-29cr-8477-rg6r, UBUNTU-CVE-2026-113436

## What is CVE-2026-113436?

CVE-2026-113436 is a high-severity vulnerability in mtrudel bandit, published on 26 Oct 2026. 

### Official description

Inefficient Algorithmic Complexity vulnerability in the header integer parser of mtrudel bandit allows an unauthenticated remote attacker to consume server CPU via a content-length value or a Host or :authority port made of thousands of digits.

Bandit.Headers.parse_integer/2 in lib/bandit/headers.ex builds the number one digit at a time with no limit on the digit count, allocating a new bignum at each step, so one value costs time quadratic in its length. It runs on raw request input over HTTP/1 and HTTP/2, before any range check. Over HTTP/2, a 4,000-digit value can be stored once in the HPACK dynamic table and re-sent on each new stream for about one byte: 124 KB of traffic kept the server busy for 27.9 s.

This issue affects bandit: from 1.0.0-pre.7 before 1.14.0.

Weakness: CWE-407 (Inefficient Algorithmic Complexity)

## Which versions are affected by CVE-2026-113436?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `bandit` | Hex | From 1.0.0-pre.7 | 1.14.0 |

## How do I fix CVE-2026-113436?

Upgrade bandit to 1.14.0 or later.

## Is CVE-2026-113436 being exploited?

There is no known exploitation of CVE-2026-113436 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-113436 and fix it if it is affected.

What it is: CVE-2026-113436 is a high-severity vulnerability in mtrudel bandit, published on 26 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-113436 in the wild and no public exploit code.

Affected packages and fixed versions:
- bandit (Hex): affected from 1.0.0-pre.7; 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-2026-113436/ (Markdown: https://insights.sbomify.com/CVE-2026-113436/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-113436
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-113436
- OSV: https://osv.dev/vulnerability/CVE-2026-113436

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-113436/
Summaries are generated and may contain mistakes; the official description above is the record.