CVE-2020-15679Network attack vector

Authenticated access via OAuth session fixation

Published Dec 22, 2022 · Updated Apr 16, 2025

OAuth session fixation in Mozilla VPN Windows before 1.2.2 allows remote attackers sharing a source IP with a victim to obtain authenticated access via a crafted login URL. The VPN login flow accepts an attacker-controlled custom URL and fails to invalidate or bind the resulting OAuth session correctly, exposing session state and permitting VPN-session disconnection. Exploitation requires convincing the victim to authenticate through that URL and being on the same source IP; the reported impact is limited to session access and disconnection.

CVSS severity7.6
High
EPSS probability0.47%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

OAuth session fixation in Mozilla VPN Windows before 1.2.2 allows remote attackers sharing a source IP with a victim to obtain authenticated access via a crafted login URL. The VPN login flow accepts an attacker-controlled custom URL and fails to invalidate or bind the resulting OAuth session correctly, exposing session state and permitting VPN-session disconnection. Exploitation requires convincing the victim to authenticate through that URL and being on the same source IP; the reported impact is limited to session access and disconnection.

The record

CVE
CVE-2020-15679
Published
Dec 22, 2022
Updated
Apr 16, 2025
Vendor
Mozilla
Product
Mozilla VPN
Classifications
CWE-384, T1539
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 22, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 16, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <1.2.2
  2. Affected versionversion=unspecified <(1360)
  3. Affected versionversion=unspecified <(929)

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mozilla · Mozilla VPNversion=unspecified <1.2.2; version=unspecified <(1360); version=unspecified <(929)

Published CVSS scores

7.6NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-384Session Fixation
T1539Steal Web Session Cookie

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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