# CVE-2023-29013: HTTP header parsing could cause a deny of service

> Attackers can cause a denial of service in Traefik by sending crafted HTTP headers that trigger excessive memory allocation during parsing.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 14 Apr 2023
- **Updated:** 13 Feb 2025
- **Also known as:** ECHO-f5d5-6383-3505, GHSA-7hj9-rv74-5g92

## What is CVE-2023-29013?

CVE-2023-29013 is a high-severity denial of service vulnerability in Traefik Traefik, published on 14 Apr 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Traefik (pronounced traffic) is a modern HTTP reverse proxy and load balancer for deploying microservices. There is a vulnerability in Go when parsing the HTTP headers, which impacts Traefik. HTTP header parsing could allocate substantially more memory than required to hold the parsed headers. This behavior could be exploited to cause a denial of service. This issue has been patched in versions 2.9.10 and 2.10.0-rc2.

Weakness: CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2023-29013?

4 open source packages ship an affected version, including github.com/traefik/traefik/v2. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/traefik/traefik/v2` | Go | All versions | 2.9.10 |
| `github.com/traefik/traefik/v2` | Go | All versions | 2.9.10 |
| `github.com/traefik/traefik/v2` | Go | From 2.10.0-rc1 | 2.10.0-rc2 |
| `github.com/traefik/traefik/v2` | Go | From 2.10.0-rc1 | 2.10.0-rc2 |

Products: Traefik Traefik.

## How do I fix CVE-2023-29013?

Upgrade github.com/traefik/traefik/v2 to a fixed version for your release line: 2.9.10 or 2.10.0-rc2.

## Is CVE-2023-29013 being exploited?

There is no known exploitation of CVE-2023-29013 in the wild and no public exploit code.

## Other vulnerabilities in Traefik Traefik

- [CVE-2024-45410](https://insights.sbomify.com/CVE-2024-45410/): HTTP client can remove the X-Forwarded headers in Traefik (critical 9.8)
- [CVE-2026-88877](https://insights.sbomify.com/CVE-2026-88877/): Traefik v3.7.0 Authentication Bypass via from-to-www-redirect (critical 9.3)
- [CVE-2026-85595](https://insights.sbomify.com/CVE-2026-85595/): Traefik before v2.11.55 and v3.0.0 through v3.7.10 Authentication Bypass via digestAuth (critical 9.3)
- [CVE-2026-88007](https://insights.sbomify.com/CVE-2026-88007/): Traefik HTTP/3 Backend NTLM Connection Reuse (critical 9.1)
- [CVE-2026-88009](https://insights.sbomify.com/CVE-2026-88009/): Traefik: Rootless HTTP/1 request-target routes as "/" but is forwarded verbatim, bypassing path-scoped routing, middleware guards and access logging (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-29013 and fix it if it is affected.

What it is: CVE-2023-29013 is a high-severity denial of service vulnerability in Traefik Traefik, published on 14 Apr 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2023-29013 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/traefik/traefik/v2 (Go): affected all versions; fixed in 2.9.10
- github.com/traefik/traefik/v2 (Go): affected all versions; fixed in 2.9.10
- github.com/traefik/traefik/v2 (Go): affected from 2.10.0-rc1; fixed in 2.10.0-rc2
- github.com/traefik/traefik/v2 (Go): affected from 2.10.0-rc1; fixed in 2.10.0-rc2

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-2023-29013/ (Markdown: https://insights.sbomify.com/CVE-2023-29013/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-29013
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-29013
- OSV: https://osv.dev/vulnerability/CVE-2023-29013

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-29013/
Summaries are generated and may contain mistakes; the official description above is the record.