CVE-2026-101158 Security Advisory 0185
An authenticated attacker can execute stored XSS via the file upload API to hijack user sessions and gain administrative access.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-101158?
CVE-2026-101158 is a critical cross-site scripting vulnerability in Arista Networks CloudVision Portal, published on 6 Oct 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
A missing input validation vulnerability in the Fileserver upload API allows an authenticated attacker with file upload privileges to execute stored cross-site scripting (XSS). Successful exploitation could enable the attacker to hijack another CloudVision user's web session, potentially granting full access to their account and administrative permissions.
Weakness: CWE-79
Which versions are affected by CVE-2026-101158?
How do I fix CVE-2026-101158?
No fix has been published for CVE-2026-101158 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-101158 being exploited?
There is no known exploitation of CVE-2026-101158 in the wild and no public exploit code.
Sources
Also known as GHSA-5qwv-x7hg-2f8r.