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PatchSiren cyber security CVE debrief

CVE-2026-73564 fatedier CVE debrief

CVE-2026-73564 is a high-severity vulnerability in frp's optional SSH Tunnel Gateway. An unauthenticated peer can exploit this vulnerability to terminate the frps process and drop active tunnels with a single five-byte request when no authorized-keys file is configured. Defenders should prioritize updating to version 0.70.1 or later and configuring an authorized-keys file for SSH authentication. This vulnerability has a significant impact on frp deployments, and defenders responsible for these deployments should assess their exposure and take necessary actions.

Vendor
fatedier
Product
frp
CVSS
HIGH 8.7
CISA KEV
Not listed in stored evidence
Original CVE published
2026-08-13
Original CVE updated
2026-09-18
Advisory published
2026-08-13
Advisory updated
2026-09-18

Who should care

Defenders responsible for frp deployments should assess exposure and prioritize updating to version 0.70.1 or later. Configuring an authorized-keys file for SSH authentication can mitigate the vulnerability.

Why it matters

CVE-2026-73564 is a high-severity vulnerability in frp's optional SSH Tunnel Gateway that can be exploited by an unauthenticated peer to terminate the frps process and drop active tunnels. Defenders should prioritize updating to version 0.70.1 or later and configuring an authorized-keys file for SSH authentication.

  • Potential termination of frps process and active tunnels
  • Unauthenticated access to SSH Tunnel Gateway
  • Possible disruption of services relying on frp

Technical summary

The frp optional SSH Tunnel Gateway has a vulnerability in pkg/ssh/server.go that allows an unauthenticated peer to terminate the frps process and drop every active tunnel with a single five-byte request when no authorized-keys file is configured. This vulnerability is caused by an integer wrap in the parsing of an SSH exec channel request. The vulnerability can be mitigated by updating to version 0.70.1 or later and configuring an authorized-keys file for SSH authentication. The vulnerability has a CVSS score of 8.7 and is considered high-severity.

Defensive priority

High

Recommended defensive actions

  • Review and update frp to version 0.70.1 or later
  • Configure an authorized-keys file for SSH authentication
  • Monitor frp logs for suspicious activity
  • Verify frp configuration and deployment
  • Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
  • Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance
  • Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed

Evidence notes

The CVE record and NVD entry provide details on the vulnerability in frp's optional SSH Tunnel Gateway. A single five-byte request can terminate the frps process and drop every active tunnel when no authorized-keys file is configured.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-73564 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-73564

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

  • CVE-2026-73564 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-73564

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

Supplemental references

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.