CVE-2026-21535 Microsoft Teams Information Disclosure Vulnerability
High 8.2
Published
Updated
Check this codebase for CVE-2026-21535 and fix it if it is affected.
What it is: CVE-2026-21535 is a high-severity vulnerability in Microsoft Teams, published on 19 Feb 2026. 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-2026-21535 in the wild and no public exploit code.
Affected product: Microsoft Teams. 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-2026-21535/ (Markdown: https://insights.sbomify.com/CVE-2026-21535/index.md)
An unauthorized attacker can disclose information over a network due to improper access control in Microsoft Teams.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-21535?
CVE-2026-21535 is a high-severity vulnerability in Microsoft Teams, published on 19 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Improper access control in Microsoft Teams allows an unauthorized attacker to disclose information over a network.
Weakness: CWE-284
Which versions are affected by CVE-2026-21535?
It affects 1 product.
Products include Microsoft Teams.
How do I fix CVE-2026-21535?
No fix has been published for CVE-2026-21535 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-21535 being exploited?
There is no known exploitation of CVE-2026-21535 in the wild and no public exploit code.
Other vulnerabilities in Microsoft Teams
- CVE-2026-65667 Microsoft Teams Elevation of Privilege Vulnerability
- CVE-2026-62896 Microsoft Teams Elevation of Privilege Vulnerability
- CVE-2026-33823 Microsoft Team Events Portal Information Disclosure Vulnerability
- CVE-2026-65767 Microsoft Teams for Android Spoofing Vulnerability
- CVE-2026-65768 Microsoft Teams Remote Code Execution Vulnerability
Sources
Also known as GHSA-rx38-cw65-cmwp.