# CVE-2017-1000100: Information disclosure in n/a

> A malicious server can trick libcurl into sending private memory contents via TFTP due to a buffer size miscalculation, requiring a patch or protocol restriction.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 4 Oct 2017
- **Updated:** 16 Apr 2026
- **Also known as:** ALPINE-CVE-2017-1000100, CLEANSTART-2026-UR08867, CURL-CVE-2017-1000100, DEBIAN-CVE-2017-1000100, DLA-1062-1, GHSA-86r8-52rx-6jcr, SUSE-SU-2017:2354-1, UBUNTU-CVE-2017-1000100

## What is CVE-2017-1000100?

CVE-2017-1000100 is a medium-severity vulnerability in Haxx Libcurl, published on 4 Oct 2017. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

When doing a TFTP transfer and curl/libcurl is given a URL that contains a very long file name (longer than about 515 bytes), the file name is truncated to fit within the buffer boundaries, but the buffer size is still wrongly updated to use the untruncated length. This too large value is then used in the sendto() call, making curl attempt to send more data than what is actually put into the buffer. The endto() function will then read beyond the end of the heap based buffer. A malicious HTTP(S) server could redirect a vulnerable libcurl-using client to a crafted TFTP URL (if the client hasn't restricted which protocols it allows redirects to) and trick it to send private memory contents to a remote server over UDP. Limit curl's redirect protocols with --proto-redir and libcurl's with CURLOPT_REDIR_PROTOCOLS.

Weakness: CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor)

## Which versions are affected by CVE-2017-1000100?

It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `curl` | SUSE:Studio Onsite 1.3 | All versions | 7.19.7-1.20.53.3.1 |

Products: Haxx Libcurl.

## How do I fix CVE-2017-1000100?

Apply the vendor's patch.

## Is CVE-2017-1000100 being exploited?

There is no known exploitation of CVE-2017-1000100 in the wild and no public exploit code.

## Other vulnerabilities in Haxx Libcurl

- [CVE-2024-6197](https://insights.sbomify.com/CVE-2024-6197/): freeing stack buffer in utf8asn1str (high 7.5)
- [CVE-2017-1000254](https://insights.sbomify.com/CVE-2017-1000254/): Memory corruption in n/a (high 7.5)
- [CVE-2016-7141](https://insights.sbomify.com/CVE-2016-7141/): Auth bypass in n/a (high 7.5)
- [CVE-2017-1000099](https://insights.sbomify.com/CVE-2017-1000099/): Information disclosure in n/a (medium 6.5)
- [CVE-2024-7264](https://insights.sbomify.com/CVE-2024-7264/): ASN.1 date parser overread (medium 6.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2017-1000100 and fix it if it is affected.

What it is: CVE-2017-1000100 is a medium-severity vulnerability in Haxx Libcurl, published on 4 Oct 2017. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2017-1000100 in the wild and no public exploit code.

Affected product: Haxx Libcurl. 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-2017-1000100/ (Markdown: https://insights.sbomify.com/CVE-2017-1000100/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-1000100
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-1000100
- OSV: https://osv.dev/vulnerability/CVE-2017-1000100

---
From sbomify Insights: https://insights.sbomify.com/CVE-2017-1000100/
Summaries are generated and may contain mistakes; the official description above is the record.