CVE-2025-20271

Published Jun 18, 2025

Last updated 24 days ago

Overview

Description
A vulnerability in the Cisco AnyConnect VPN server of Cisco Meraki MX and Cisco Meraki Z Series Teleworker Gateway devices could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition in the Cisco AnyConnect service on an affected device. This vulnerability is due to variable initialization errors when an SSL VPN session is established. An attacker could exploit this vulnerability by sending a sequence of crafted HTTPS requests to an affected device. A successful exploit could allow the attacker to cause the Cisco AnyConnect VPN server to restart, resulting in the failure of all established SSL VPN sessions and forcing remote users to initiate a new VPN connection and re-authenticate. A sustained attack could prevent new SSL VPN connections from being established, effectively making the Cisco AnyConnect VPN service unavailable for all legitimate users.
Source
psirt@cisco.com
NVD status
Awaiting Analysis

Risk scores

CVSS 3.1

Type
Primary
Base score
8.6
Impact score
4
Exploitability score
3.9
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Severity
HIGH

Weaknesses

psirt@cisco.com
CWE-457

Social media

Hype score
Not currently trending
  1. ⚠️Vulnerabilidad corregida en productos de Cisco ❗CVE-2025-20271 ➡️Más info: https://t.co/t47aeS2bYM https://t.co/6q0A89RkQB

    @CERTpy

    24 Jun 2025

    170 Impressions

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  2. ⚠️Vulnerabilidad corregida en productos de Cisco ❗CVE-2025-20271 ➡️Más info: https://t.co/KnBMFFbcEG https://t.co/bx2nCDYFuz

    @CERTpy

    23 Jun 2025

    157 Impressions

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  3. CVE-2025-20271 (CVSS:8.6, HIGH) is Received. A vulnerability in the Cisco AnyConnect VPN server of Cisco Meraki MX and Cisco Meraki Z Series Teleworker Gateway devic..https://t.co/S0UeNa6EoX #cybersecurityawareness #cybersecurity #CVE #infosec #hacker #nvd #mitre

    @cracbot

    23 Jun 2025

    13 Impressions

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  4. Actively exploited CVE : CVE-2025-20271

    @transilienceai

    22 Jun 2025

    16 Impressions

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  5. Actively exploited CVE : CVE-2025-20271

    @transilienceai

    21 Jun 2025

    21 Impressions

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  6. Cisco Meraki MX and Z Series AnyConnect VPN Authentication Denial of Service Vulnerability (CVE-2025-20271) #Cisco #CiscoMeraki #CVE202520271 #CyberSecurity https://t.co/kEsvJaC8Nk https://t.co/EeWgmiXuDI

    @SystemTek_UK

    19 Jun 2025

    58 Impressions

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  7. CVE-2025-20271 A vulnerability in the Cisco AnyConnect VPN server of Cisco Meraki MX and Cisco Meraki Z Series Teleworker Gateway devices could allow an unauthenticated, remote atta… https://t.co/ztKv8ubiFl

    @CVEnew

    19 Jun 2025

    135 Impressions

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  8. High-Severity Vulnerabilities Patched by Cisco and Atlassian Cisco and Atlassian have released patches addressing multiple high-severity vulnerabilities that could lead to denial-of-service (DoS) conditions. Cisco fixed CVE-2025-20271 (CVSS 8.6), a remotely exploitable bug in ht

    @dCypherIO

    19 Jun 2025

    34 Impressions

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