# CVE-2017-8911: Integer overflow in n/a

> An integer underflow in the TNEF library allows attackers to trigger invalid writes, potentially leading to arbitrary code execution.

- **Severity:** Critical 9.8 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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:** 12 May 2017
- **Updated:** 5 Aug 2024
- **Also known as:** DEBIAN-CVE-2017-8911, DLA-962-1, DSA-3869-1, GHSA-575j-8r4j-2fmq, MGASA-2017-0209, UBUNTU-CVE-2017-8911, openSUSE-SU-2024:11467-1

## What is CVE-2017-8911?

CVE-2017-8911 is a critical vulnerability in n/a, published on 12 May 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An integer underflow has been identified in the unicode_to_utf8() function in tnef 1.4.14. This might lead to invalid write operations, controlled by an attacker.

Weakness: CWE-191 (Integer Underflow (Wrap or Wraparound))

## Which versions are affected by CVE-2017-8911?

It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `tnef` | openSUSE:Tumbleweed | All versions | 1.4.18-1.6 |

Products: Tnef Project Tnef.

## How do I fix CVE-2017-8911?

Apply the vendor's patch.

## Is CVE-2017-8911 being exploited?

There is no known exploitation of CVE-2017-8911 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2026-103679](https://insights.sbomify.com/CVE-2026-103679/): Tnef: use-after-free and double-free in get_body_files() via multi-value body extraction (medium 6.5)
- [CVE-2026-103678](https://insights.sbomify.com/CVE-2026-103678/): Tnef: heap out-of-bounds read in get_rtf_data_from_buf() via uncompressed rtf mapi value (medium 5.4)
- [CVE-2026-103680](https://insights.sbomify.com/CVE-2026-103680/): Tnef: heap buffer overflow in find_free_number() via numbered-backup suffix generation (low 3.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2017-8911 and fix it if it is affected.

What it is: CVE-2017-8911 is a critical vulnerability in n/a, published on 12 May 2017. 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-2017-8911 in the wild and no public exploit code.

Affected product: n/a. 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-2017-8911/ (Markdown: https://insights.sbomify.com/CVE-2017-8911/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-8911
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-8911
- OSV: https://osv.dev/vulnerability/CVE-2017-8911

---
From sbomify Insights: https://insights.sbomify.com/CVE-2017-8911/
Summaries are generated and may contain mistakes; the official description above is the record.