- Published
- Source
- Help Net Security
- Reported by
- 5 publishers
- Filed under
- Ransomware, Attacks, Malware & exploits
- Vulnerabilities
- 1 CVE Exploited
Several ransomware groups are exploiting CVE-2026-0257, an authentication bypass in Palo Alto Networks’ PAN-OS GlobalProtect patched in May, to break into organizations in sectors ranging from healthcare and education to government and energy. CVE-2026-0257 stems from the firewalls relying on cookies without performing detailed validation and integrity checking, which allows remote, unauthenticated attackers to bypass security restrictions and establish an unauthorized VPN connection. The vulnerabilities affect the GlobalProtect portal and gateway of PAN’s physical and … More →…
If you run the affected product
- Find every instance – especially the ones reachable from the internet.
- Apply the vendor's patch or mitigation now: exploited flaws are fixed in days, not at the next patch cycle.
- Then check for signs it was used before you patched: web shells, new accounts, unusual outbound traffic.
More helpCISA's Known Exploited Vulnerabilities catalogue (opens in a new tab)
Also reported by 4 more publishers
The vulnerabilities in this story
CVE-2026-0257 in the NVD (opens in a new tab)
- CVSS9.1Critical
- CISA KEVExploitedon the list since 29 May · used in ransomware
Exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog (CC0). Exploit prediction: EPSS by FIRST. This product uses the NVD API but is not endorsed or certified by the NVD.
Defender’s notebook
The attacker technique behind this story, in MITRE’s terms – and what to check in your own estate.
Data Encrypted for Impact
ImpactWhat a defender checks
- Isolate affected hosts from the network to stop the spread.
- Confirm backups are offline and restorable – then test a restore.
- Hunt for what came first: new admin accounts, disabled security tools, remote-access software.
Build the skillBlue Team Engineer · Incident Management & Response Engineering
External Remote Services
Persistence, Initial AccessWhat a defender checks
- List every VPN, remote desktop and remote-access gateway you expose.
- Require MFA on all of them, and keep them patched.
- Alert on sign-ins from new countries, networks or devices.
Build the skillBlue Team Engineer · Network Security Engineering
© 2026 The MITRE Corporation. This work is reproduced and distributed with the permission of The MITRE Corporation. MITRE ATT&CK and ATT&CK are registered trademarks of The MITRE Corporation.
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