# CVE-2025-53007: arduino-esp32 vulnerable to CRLF injection in WebServer.cpp

> Attackers can inject CRLF characters into HTTP headers via the sendHeader function, enabling HTTP response splitting and header manipulation in ESP32 applications.

- **Severity:** High 8.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 26 Jun 2025
- **Updated:** 27 Jun 2025
- **Also known as:** GHSA-5476-9jjq-563m

## What is CVE-2025-53007?

CVE-2025-53007 is a high-severity vulnerability in espressif arduino-esp32, published on 26 Jun 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

arduino-esp32 provides an Arduino core for the ESP32. Versions prior to 3.3.0-RC1 and 3.2.1 contain a HTTP Response Splitting vulnerability. The `sendHeader` function takes arbitrary input for the HTTP header name and value, concatenates them into an HTTP header line, and appends this to the outgoing HTTP response headers. There is no validation or sanitization of the `name` or `value` parameters before they are included in the HTTP response. If an attacker can control the input to `sendHeader` (either directly or indirectly), they could inject carriage return (`\r`) or line feed (`\n`) characters into either the header name or value. This could allow the attacker to inject additional headers, manipulate the structure of the HTTP response, potentially inject an entire new HTTP response (HTTP Response Splitting), and/or ause header confusion or other HTTP protocol attacks. Versions 3.3.0-RC1 and 3.2.1 contain a fix for the issue.

Weakness: CWE-113 (Improper Neutralization of CRLF Sequences in HTTP Headers)

## Which versions are affected by CVE-2025-53007?


## How do I fix CVE-2025-53007?

No fix has been published for CVE-2025-53007 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-53007 being exploited?

There is no known exploitation of CVE-2025-53007 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-53007 and fix it if it is affected.

What it is: CVE-2025-53007 is a high-severity vulnerability in espressif arduino-esp32, published on 26 Jun 2025. 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-2025-53007 in the wild and no public exploit code.

Affected product: espressif arduino-esp32. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2025-53007/ (Markdown: https://insights.sbomify.com/CVE-2025-53007/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-53007
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-53007
- OSV: https://osv.dev/vulnerability/CVE-2025-53007

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From sbomify Insights: https://insights.sbomify.com/CVE-2025-53007/
Summaries are generated and may contain mistakes; the official description above is the record.