# CVE-2011-1475: Apache Tomcat HTTP BIO Connector Error Discloses Information From Different Requests to Remote Users

> Remote attackers can read responses intended for other clients due to improper HTTP pipelining handling in Apache Tomcat.

- **Severity:** Medium 5.0 (`AV:N/AC:L/Au:N/C:P/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 8 Apr 2011
- **Updated:** 6 Aug 2024
- **Also known as:** GHSA-h6c8-rg87-f3pc

## What is CVE-2011-1475?

CVE-2011-1475 is a medium-severity vulnerability in Apache Tomcat, published on 8 Apr 2011. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The HTTP BIO connector in Apache Tomcat 7.0.x before 7.0.12 does not properly handle HTTP pipelining, which allows remote attackers to read responses intended for other clients in opportunistic circumstances by examining the application data in HTTP packets, related to "a mix-up of responses for requests from different users."

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2011-1475?

2 open source packages ship an affected version, including org.apache.tomcat:tomcat. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `org.apache.tomcat:tomcat` | Maven | From 7.0.0 | 7.0.12 |
| `org.apache.tomcat:tomcat` | Maven | From 7.0.0 | 7.0.12 |

Products: Apache Tomcat.

## How do I fix CVE-2011-1475?

Upgrade org.apache.tomcat:tomcat to 7.0.12 or later.

## Is CVE-2011-1475 being exploited?

There is no known exploitation of CVE-2011-1475 in the wild and no public exploit code.

Public exploit code:

- Check with Maven on CVE-2011-1475 (github_poc): https://github.com/samaujs/CVE-2011-1475

## Other vulnerabilities in Apache Tomcat

- [CVE-2025-24813](https://insights.sbomify.com/CVE-2025-24813/): Apache Tomcat Path Equivalence (critical 10.0, exploited in the wild)
- [CVE-2016-8735](https://insights.sbomify.com/CVE-2016-8735/): Apache Tomcat Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2017-12617](https://insights.sbomify.com/CVE-2017-12617/): Apache Tomcat Remote Code Execution (high 8.1, exploited in the wild)
- [CVE-2017-12615](https://insights.sbomify.com/CVE-2017-12615/): Apache Tomcat on Windows Remote Code Execution (high 8.1, exploited in the wild)
- [CVE-2026-34486](https://insights.sbomify.com/CVE-2026-34486/): Apache Tomcat Missing Encryption of Sensitive Data (high 7.5, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2011-1475 and fix it if it is affected.

What it is: CVE-2011-1475 is a medium-severity vulnerability in Apache Tomcat, published on 8 Apr 2011. 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-2011-1475 in the wild and no public exploit code.

Affected packages and fixed versions:
- org.apache.tomcat:tomcat (Maven): affected from 7.0.0; fixed in 7.0.12
- org.apache.tomcat:tomcat (Maven): affected from 7.0.0; fixed in 7.0.12

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-2011-1475/ (Markdown: https://insights.sbomify.com/CVE-2011-1475/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2011-1475
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2011-1475
- OSV: https://osv.dev/vulnerability/CVE-2011-1475

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From sbomify Insights: https://insights.sbomify.com/CVE-2011-1475/
Summaries are generated and may contain mistakes; the official description above is the record.