A remote code execution vulnerability exists in Microsoft Word software when it fails to properly handle objects in memory. An attacker who successfully exploited the vulnerability could use a specially crafted file to perform actions in the security context of the current user. For example, the file could then take actions on behalf of the logged-on user with the same permissions as the current user.
To exploit the vulnerability, a user must open a specially crafted file with an affected version of Microsoft Word software. In an email attack scenario, an attacker could exploit the vulnerability by sending the specially crafted file to the user and convincing the user to open the file. In a web-based attack scenario, an attacker could host a website (or leverage a compromised website that accepts or hosts user-provided content) that contains a specially crafted file that is designed to exploit the vulnerability. However, an attacker would have no way to force the user to visit the website. Instead, an attacker would have to convince the user to click a link, typically by way of an enticement in an email or Instant Messenger message, and then convince the user to open the specially crafted file.
The security update addresses the vulnerability by correcting how Microsoft Word handles files in memory.
## Which versions are affected by CVE-2020-1338? It affects 4 products. Products: Microsoft 365 Apps, Microsoft Office, Microsoft Office Online Server, Microsoft Sharepoint Server. ## How do I fix CVE-2020-1338? No fix has been published for CVE-2020-1338 yet. Limit exposure of the affected software until one is available. ## Is CVE-2020-1338 being exploited? There is no known exploitation of CVE-2020-1338 in the wild and no public exploit code. ## Other vulnerabilities in Microsoft 365 Apps - [CVE-2024-21413](https://insights.sbomify.com/CVE-2024-21413/): Microsoft Outlook Improper Input Validation (critical 9.8, exploited in the wild) - [CVE-2023-23397](https://insights.sbomify.com/CVE-2023-23397/): Microsoft Office Outlook Privilege Escalation (critical 9.8, exploited in the wild) - [CVE-2024-38189](https://insights.sbomify.com/CVE-2024-38189/): Microsoft Project Remote Code Execution Vulnerability (high 8.8, exploited in the wild) - [CVE-2023-35311](https://insights.sbomify.com/CVE-2023-35311/): Microsoft Outlook Security Feature Bypass (high 8.8, exploited in the wild) - [CVE-2026-21514](https://insights.sbomify.com/CVE-2026-21514/): Microsoft Office Word Reliance on Untrusted Inputs in a Security Decision (high 7.8, exploited in the wild) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2020-1338 and fix it if it is affected. What it is: CVE-2020-1338 is a high-severity memory corruption vulnerability in Microsoft 365 Apps, published on 11 Sep 2020. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link. Exploitation: There is no known exploitation of CVE-2020-1338 in the wild and no public exploit code. Affected product: Microsoft 365 Apps. 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-2020-1338/ (Markdown: https://insights.sbomify.com/CVE-2020-1338/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2020-1338 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-1338 - OSV: https://osv.dev/vulnerability/CVE-2020-1338 --- From sbomify Insights: https://insights.sbomify.com/CVE-2020-1338/ Summaries are generated and may contain mistakes; the official description above is the record.