CVE-2026-102764: BeyondTrust Remote Support Authentication Bypass by Spoofing Vulnerability
BeyondTrust Remote Support contains an authentication bypass by spoofing vulnerability that could allow a remote attacker to perform file operations on the appliance.
Overview
BeyondTrust Remote Support contains an authentication bypass flaw in its internal messaging components, which fail to validate the origin of messages they receive. A remote, unauthenticated attacker can spoof message origins to make the appliance treat crafted requests as trusted, then perform file operations on the system. All versions through 26.2.3 are affected; SaaS customers received a patch automatically, while self-hosted deployments require manual application.
Vulnerability details
The flaw is classified under CWE-290 (Authentication Bypass by Spoofing), a weakness where a system grants trust based on an unverified origin claim. In BeyondTrust Remote Support, internal messaging components process messages without adequately confirming where those messages originate. Because the trust decision relies on an origin identifier that is neither authenticated nor sufficiently validated, the boundary between untrusted external input and trusted internal communication collapses. An attacker who can reach the appliance over the network can present a message that appears to come from a trusted internal source.
An unauthenticated remote attacker sends crafted messages with spoofed origin identifiers to the internal messaging component of the Remote Support appliance. Because no authentication is required and the component accepts the forged origin as legitimate, the appliance processes the message as a trusted internal instruction. The attacker gains the ability to perform file operations on the appliance, with potential for full confidentiality, integrity, and availability impact. The facts do not confirm whether the reachable interface is the management plane or a public-facing endpoint, so network exposure should be assessed per deployment.
Severity and impact
Exploitation status
This vulnerability is confirmed as actively exploited in the wild — it is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog.
Detection and monitoring
- Review appliance audit logs for file operation events (reads, writes, deletes) that have no corresponding authenticated user session or administrative action in the same timeframe, which would indicate activity driven by unauthenticated internal messaging.
- Monitor for unexpected inbound connections to internal messaging ports or interfaces from sources outside the defined peer or management network, particularly from internet-facing addresses on self-hosted deployments running version 26.2.3 or earlier.
Remediation
Additional hardening
- For self-hosted Remote Support instances running versions 24.3.1 through 26.2.3, apply the BT26-05-RS patch immediately; instances older than 24.3.1 must first upgrade to a patchable version (25.1.7 is available for this purpose) before applying the patch.
- Restrict network access to the Remote Support appliance's management and internal messaging interfaces using firewall rules or network segmentation, limiting inbound connections to known administrative source addresses only.
- If patching cannot be applied immediately, consider taking internet-exposed self-hosted appliances offline or placing them behind a VPN or access-controlled gateway to reduce the attack surface while remediation is prepared.
- Conduct forensic triage on any self-hosted appliance that was internet-reachable before patching, reviewing file system changes and internal messaging logs for evidence of unauthorized file operations, consistent with CISA forensic triage guidance referenced in the advisory.
Key dates
References
- https://nvd.nist.gov/vuln/detail/CVE-2026-102764
- https://www.beyondtrust.com/trust-center/security-advisories/bt26-05
- https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk
- https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk
- https://beyondtrustcorp.service-now.com/csm?id=csm_kb_article&sysparm_article=KB0024066
- https://www.beyondtrust.com/blog/entry/bt26-05
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-102764
Frequently asked questions
Does CVE-2026-102764 affect my FedRAMP authorization?
If BeyondTrust Remote Support runs inside your authorization boundary, CVE-2026-102764 affects your FedRAMP authorization directly. CISA has listed this vulnerability in its Known Exploited Vulnerabilities (KEV) catalog with a remediation deadline of October 19, 2026. An unpatched KEV inside your boundary is an assessor finding. You must either remediate it or formally document a mitigation before your assessor and sponsoring agency raise it during review.
How does Knox help me handle CVE-2026-102764?
Knox does not patch BeyondTrust Remote Support on your behalf. Under the FedRAMP shared-responsibility model, remediating CVE-2026-102764 is your obligation. What Knox provides is the pre-authorized, single-tenant boundary to remediate within, along with Knox's automated continuous monitoring platform and audit-artifact coverage to document the fix for your next assessment. The work of applying the patch is yours; managing your compliance posture while you do it is not something you handle alone.
How does Knox's monitoring help with vulnerabilities like this?
Knox's automated continuous monitoring platform watches your environment for newly disclosed vulnerabilities and compliance issues on a continuous basis. When CVE-2026-102764 or a similar exposure surfaces, it appears during ongoing monitoring rather than only when an assessor flags it at a scheduled review, giving your team time to act before the finding becomes a formal problem.
How do I get FedRAMP authorized with Knox?
Knox runs a FedRAMP-as-a-Service platform. It gives SaaS vendors a pre-authorized cloud boundary on AWS, Azure, and GCP. Your application inherits 60-80% of the required security controls. You reach FedRAMP authorization in about 90 days for roughly 90% less than the traditional $3.5M path. Book a meeting and Knox will map your path to authorization.
What happens if CVE-2026-102764 isn't remediated by October 19, 2026?
An unremediated CVE-2026-102764 becomes a Plan of Action and Milestones (POA&M) item. A growing POA&M list turns what would otherwise be a routine continuous-monitoring review into a difficult conversation with your sponsoring agency. Closing the item out and documenting the remediation history is what keeps your authorization clean and the agency relationship intact.
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