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PatchSiren cyber security CVE debrief

CVE-2026-0257 Palo Alto Networks CVE debrief

Palo Alto Networks PAN-OS contains an authentication bypass vulnerability. CISA added this issue to the Known Exploited Vulnerabilities catalog on 2026-05-29 with a remediation due date of 2026-06-01, indicating active exploitation in the wild. Federal agencies and organizations following CISA guidance must apply mitigations by the due date. The exact affected versions, root cause, and complete attack vector details are not available in the supplied source corpus; only the vulnerability classification and remediation urgency are confirmed.

Vendor
Palo Alto Networks
Product
PAN-OS
CVSS
CRITICAL 9.3
CISA KEV
Listed
Original CVE published
2026-05-29
Original CVE updated
2026-05-29
Advisory published
2026-05-29
Advisory updated
2026-05-29

Who should care

Organizations running Palo Alto Networks PAN-OS, especially federal agencies subject to CISA BOD 22-01, security operations teams managing firewall and network security infrastructure, and compliance officers tracking KEV remediation deadlines.

Technical summary

Authentication bypass in Palo Alto Networks PAN-OS. CVSS 7.8 HIGH. Added to CISA KEV 2026-05-29 with remediation due 2026-06-01. Specific affected versions and technical root cause not detailed in supplied sources.

Defensive priority

critical

Recommended defensive actions

  • Apply vendor-provided mitigations or patches for Palo Alto Networks PAN-OS as soon as they become available.
  • Follow CISA BOD 22-01 guidance for cloud services if applicable to your environment.
  • If mitigations or patches are unavailable, evaluate discontinuing use of affected PAN-OS instances until remediation is possible.
  • Monitor Palo Alto Networks security advisories and CISA KEV updates for additional technical details and version-specific guidance.
  • Review authentication logs and access controls on PAN-OS-managed infrastructure for indicators of unauthorized access.

Evidence notes

Source corpus confirms: (1) CISA KEV listing with active-exploitation status and BOD 22-01 binding operational directive applicability; (2) vendor attribution to Palo Alto Networks PAN-OS; (3) CVSS 7.8 HIGH severity; (4) KEV due date of 2026-06-01. No technical details on affected versions, exploit mechanism, or patch availability are present in the supplied corpus.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-0257 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-0257

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-0257 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-0257

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

  • CISA Known Exploited Vulnerabilities catalog

    Publisher, destination, and source semantics verified

    URL: https://www.cisa.gov/known-exploited-vulnerabilities-catalog

    Cybersecurity and Infrastructure Security Agency - Official CISA catalog of vulnerabilities known to be exploited in the wild.

Supplemental references

  • Source item URL

    Unverified legacy reference

    URL: https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json

    cisa_kev

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.