Palo Alto says attackers are exploiting GlobalProtect VPN auth bypass flaw CVE-2026-0257

Palo Alto Networks says attackers are now using a GlobalProtect VPN flaw to try to get into corporate networks without valid credentials. The issue, CVE-2026-0257, affects PAN-OS GlobalProtect portal and gateway configurations that use authentication override cookies with specific certificate reuse; attackers can forge those cookies and establish unauthorized VPN access on unpatched devices. Rapid7 says it saw exploitation from at least May 17, 2026, and CISA has added the flaw to its Known Exploited Vulnerabilities catalog.
Why it matters: Organizations that use Palo Alto GlobalProtect could be exposed to unauthorized remote access into internal networks, so this is an urgent patch-now issue. Defenders should update PAN-OS immediately and, if needed, disable authentication override cookies or use a separate certificate for that feature.

Sources

Palo Alto Warns of Active Exploitation of PAN-OS GlobalProtect VPN Flaw
info@thehackernews.com (The Hacker News) 2026.06.15 99% relevant
This is the same underlying event: Palo Alto warning that attackers are actively exploiting the PAN-OS GlobalProtect VPN authentication-bypass flaw CVE-2026-0257 on affected systems.
Arctic Wolf Observes an Increase in Palo Alto Networks GlobalProtect Authentication Bypass Exploitation via CVE-2026-0257
Arctic Wolf Labs 2026.06.11 97% relevant
This directly updates the same CVE-2026-0257 exploitation story by adding observed timing of exploitation waves, the role of published exploit code, required configuration conditions, and follow-on activity including IPSec tunnel establishment and Impacket-style SMB/NTLM reconnaissance after successful bypass.
Palo Alto VPN bug graduates from advisory to active exploitation
2026.06.01 98% relevant
This article is the same underlying event and adds specifics that Rapid7 observed successful exploitation in multiple customer environments as early as May 17, saw attackers establish unauthorized VPN sessions, and notes the flaw has been added to CISA's KEV catalog with a federal patch deadline.
Recent Palo Alto Networks Vulnerability Exploited for Weeks
Ionut Arghire 2026.06.01 97% relevant
This directly updates the same CVE-2026-0257 event by adding that exploitation began on May 17, four days after disclosure; describing Rapid7's observed waves from Vultr and Dromatics Systems; noting forged-cookie abuse and partial VPN session establishment; and pointing defenders to Rapid7's PoC scanner and indicators of compromise.
Palo Alto GlobalProtect VPN auth bypass flaw now exploited in attacks
Lawrence Abrams 2026.05.30 100% relevant
This article establishes a new tracked event by confirming active exploitation of Palo Alto PAN-OS GlobalProtect CVE-2026-0257 and linking it to urgent mitigation and KEV listing.
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