# CVE-2026-108529: SETTINGS and stream-0 WINDOW_UPDATE frames trigger quadratic work over blocked streams 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-2026-108529, GHSA-j363-h72p-296m, UBUNTU-CVE-2026-108529

## What is CVE-2026-108529?

CVE-2026-108529 is a high-severity vulnerability in mtrudel bandit, published on 26 Oct 2026. 

### Official description

Inefficient Algorithmic Complexity vulnerability in the HTTP/2 implementation of mtrudel bandit allows an unauthenticated remote attacker to exhaust server CPU via small SETTINGS or connection-level WINDOW_UPDATE frames. The attacker opens thousands of streams whose responses block on the connection send window, then sends cheap frames that each make the server walk the whole queue of blocked sends. In the reporter's run, with 3,000 blocked streams a single 9-byte SETTINGS frame took 133 ms to process.

do_pending_sends/2 in lib/bandit/http2/connection.ex retries every queued send and, before each retry, removes that entry from the queue with List.delete/2, so one frame costs O(n²) list operations for n blocked streams. max_concurrent_streams defaults to :infinity, so the attacker chooses n.

This issue affects bandit: from 0.3.4 before 1.14.0.

Weakness: CWE-407 (Inefficient Algorithmic Complexity)

## Which versions are affected by CVE-2026-108529?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `bandit` | Hex | From 0.3.4 | 1.14.0 |

## How do I fix CVE-2026-108529?

Upgrade bandit to 1.14.0 or later.

## Is CVE-2026-108529 being exploited?

There is no known exploitation of CVE-2026-108529 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-108529 and fix it if it is affected.

What it is: CVE-2026-108529 is a high-severity vulnerability in mtrudel bandit, published on 26 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-108529 in the wild and no public exploit code.

Affected packages and fixed versions:
- bandit (Hex): affected from 0.3.4; 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-2026-108529/ (Markdown: https://insights.sbomify.com/CVE-2026-108529/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-108529
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-108529
- OSV: https://osv.dev/vulnerability/CVE-2026-108529

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-108529/
Summaries are generated and may contain mistakes; the official description above is the record.