# CVE-2019-1084: Information disclosure in Mail and Calendar

> An authenticated attacker can hide entities in conversations by using non-printable characters in display names, leading to information disclosure.

- **Severity:** Medium 6.5 (`CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 15 Jul 2019
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-r2c7-qvrq-pwg6

## What is CVE-2019-1084?

CVE-2019-1084 is a medium-severity vulnerability in Microsoft Exchange Server, published on 15 Jul 2019. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

An information disclosure vulnerability exists when Exchange allows creation of entities with Display Names having non-printable characters. An authenticated attacker could exploit this vulnerability by creating entities with invalid display names, which, when added to conversations, remain invisible. This security update addresses the issue by validating display names upon creation in Microsoft Exchange, and by rendering invalid display names correctly in Microsoft Outlook clients., aka 'Microsoft Exchange Information Disclosure Vulnerability'.

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

## Which versions are affected by CVE-2019-1084?

It affects 9 products.


Products: Microsoft Exchange Server, Microsoft Lync, Microsoft Lync Basic, Microsoft Mail and Calendar, Microsoft Office, Microsoft Office 365 Proplus, Microsoft Outlook, Microsoft Skype for Business, Microsoft Skype for Business Basic.

## How do I fix CVE-2019-1084?

No fix has been published for CVE-2019-1084 yet. Limit exposure of the affected software until one is available.

## Is CVE-2019-1084 being exploited?

There is no known exploitation of CVE-2019-1084 in the wild and no public exploit code.

## Other vulnerabilities in Microsoft Exchange Server

- [CVE-2024-21410](https://insights.sbomify.com/CVE-2024-21410/): Microsoft Exchange Server Privilege Escalation (critical 9.8, exploited in the wild)
- [CVE-2021-34473](https://insights.sbomify.com/CVE-2021-34473/): Microsoft Exchange Server Remote Code Execution (critical 9.1, exploited in the wild)
- [CVE-2021-26855](https://insights.sbomify.com/CVE-2021-26855/): Microsoft Exchange Server Remote Code Execution (critical 9.1, exploited in the wild)
- [CVE-2021-34523](https://insights.sbomify.com/CVE-2021-34523/): Microsoft Exchange Server Privilege Escalation (critical 9.0, exploited in the wild)
- [CVE-2023-21529](https://insights.sbomify.com/CVE-2023-21529/): Microsoft Exchange Server Deserialization of Untrusted Data (high 8.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-1084 and fix it if it is affected.

What it is: CVE-2019-1084 is a medium-severity vulnerability in Microsoft Exchange Server, published on 15 Jul 2019. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2019-1084 in the wild and no public exploit code.

Affected product: Microsoft Exchange Server. 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-2019-1084/ (Markdown: https://insights.sbomify.com/CVE-2019-1084/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-1084
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-1084
- OSV: https://osv.dev/vulnerability/CVE-2019-1084

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-1084/
Summaries are generated and may contain mistakes; the official description above is the record.