# CVE-2026-110499: Client-chosen HPACK encoder table size is applied uncapped, growing per-connection state with every response 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-2026-110499, GHSA-47x4-3fxf-82fr, UBUNTU-CVE-2026-110499

## What is CVE-2026-110499?

CVE-2026-110499 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/2 implementation of mtrudel bandit allows an unauthenticated remote attacker to grow per-connection memory and CPU cost without bound via a large SETTINGS_HEADER_TABLE_SIZE. Bandit resizes its HPACK encoder table to whatever size the client advertises, up to 2^32-1 bytes, and indexes response headers into it. Because responses carry distinct values such as date or content-length, nothing is evicted and the table grows with every response for the life of the connection, while each lookup scans it linearly.

The SETTINGS handling in Bandit.HTTP2.Connection (lib/bandit/http2/connection.ex) passes remote_settings.header_table_size to HPAX.resize/2 with no server-side cap, and encode_headers encodes every response header as :store. Serving N responses on one connection therefore costs O(N²) CPU in the connection process.

This issue affects bandit: from 0.3.6 before 1.14.0.

Weakness: CWE-770 (Allocation of Resources Without Limits or Throttling)

## Which versions are affected by CVE-2026-110499?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `bandit` | Hex | From 0.3.6 | 1.14.0 |

## How do I fix CVE-2026-110499?

Upgrade bandit to 1.14.0 or later.

## Is CVE-2026-110499 being exploited?

There is no known exploitation of CVE-2026-110499 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-110499 and fix it if it is affected.

What it is: CVE-2026-110499 is a high-severity vulnerability in mtrudel bandit, published on 26 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-110499 in the wild and no public exploit code.

Affected packages and fixed versions:
- bandit (Hex): affected from 0.3.6; 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-2026-110499/ (Markdown: https://insights.sbomify.com/CVE-2026-110499/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-110499
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-110499
- OSV: https://osv.dev/vulnerability/CVE-2026-110499

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-110499/
Summaries are generated and may contain mistakes; the official description above is the record.