CVE-2026-77910 Microsoft Exchange Server Elevation of Privilege Vulnerability
High 8.8
Published
Updated
Check this codebase for CVE-2026-77910 and fix it if it is affected.
What it is: CVE-2026-77910 is a high-severity vulnerability in Microsoft Exchange Server 2016 Cumulative Update 23, published on 13 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-77910 in the wild and no public exploit code.
Affected product: Microsoft Exchange Server 2016 Cumulative Update 23. 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-2026-77910/ (Markdown: https://insights.sbomify.com/CVE-2026-77910/index.md)
An authorized attacker can elevate privileges on Microsoft Exchange Server due to incorrect authorization checks.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-77910?
CVE-2026-77910 is a high-severity vulnerability in Microsoft Exchange Server 2016 Cumulative Update 23, published on 13 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Incorrect authorization in Microsoft Exchange Server allows an authorized attacker to elevate privileges over a network.
Weakness: CWE-863
Which versions are affected by CVE-2026-77910?
How do I fix CVE-2026-77910?
No fix has been published for CVE-2026-77910 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-77910 being exploited?
There is no known exploitation of CVE-2026-77910 in the wild and no public exploit code.
Sources
Also known as GHSA-8324-3q3h-54w9.