# CVE-2026-12254: Netskope Client Captive Portal WebView Persistence allowing SWG bypass issue

> Attackers can bypass Secure Web Gateway protections via rogue captive portals, enabling access to malicious sites or data exfiltration.

- **Severity:** Medium 6.4 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:H/SI:H/SA:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 19 Oct 2026
- **Updated:** 21 Oct 2026
- **Also known as:** GHSA-4fcp-xcp9-9vm6

## What is CVE-2026-12254?

CVE-2026-12254 is a medium-severity vulnerability in Netskope Client, published on 19 Oct 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

Netskope is notified about a potential gap in its agent (NSClient) where a system with Netskope Client while connecting to an access point with Captive Portal switches to a Network which already has internet connectivity, the Captive Portal does not close. This allows the possibility of abuse via the Captive Portal using a rogue access point to either access malicious sites or exfiltrate data.The issue impacts all versions prior to R142

Weakness: CWE-613 (DEPRECATED: Insufficient Session Expiration)

## Which versions are affected by CVE-2026-12254?


## How do I fix CVE-2026-12254?

No fix has been published for CVE-2026-12254 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-12254 being exploited?

There is no known exploitation of CVE-2026-12254 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-12254 and fix it if it is affected.

What it is: CVE-2026-12254 is a medium-severity vulnerability in Netskope Client, published on 19 Oct 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-12254 in the wild and no public exploit code.

Affected product: Netskope Client. 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-2026-12254/ (Markdown: https://insights.sbomify.com/CVE-2026-12254/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-12254
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-12254
- OSV: https://osv.dev/vulnerability/CVE-2026-12254

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-12254/
Summaries are generated and may contain mistakes; the official description above is the record.