CVE-2026-102507 in Sliver
Summary
by MITRE • 09/29/2026
Sliver C2 framework version 1.7.7 and earlier contains an unhandled panic vulnerability in the operator gRPC handler that allows an attacker controlling a compromised implant to crash the entire teamserver by returning a malformed or empty Download response. Attackers can send zero-length or 1-3 byte data payloads through a hostile implant session to trigger an out-of-bounds slice access in the vendored Binject library's BinaryMagic function, which propagates unrecovered through the operator gRPC interceptor chain and terminates the server process, affecting all connected operators.
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Analysis
by VulDB Data Team • 09/29/2026
The Sliver Command and Control framework version 1.7.7 and earlier contains a critical unhandled panic vulnerability within its operator gRPC handler architecture that poses a significant risk to operational stability. This flaw specifically affects teamserver instances when interacting with compromised implants, allowing an attacker who controls such an implant to trigger a denial of service condition against the entire command infrastructure. The root cause lies in insufficient input validation and error handling mechanisms during the processing of download requests initiated by operators but executed through hostile or untrusted implant sessions. When these interactions occur under specific conditions involving malformed data structures, the system fails to gracefully manage the exception, leading directly to a server-side crash that disrupts all active operator connections simultaneously.
The technical mechanism behind this vulnerability involves an out-of-bounds slice access error occurring within the vendored Binject library's BinaryMagic function. This internal component is responsible for parsing binary data structures associated with file downloads and other payload operations. When an attacker sends a zero-length or extremely small payload consisting of one to three bytes through a compromised implant session, the parser attempts to read beyond the allocated memory boundaries of the slice buffer. Because this out-of-bounds access triggers a runtime panic in Go that is not caught by any surrounding error handling logic within the operator gRPC interceptor chain, the exception propagates upward without recovery. Consequently, the teamserver process terminates abruptly rather than returning an appropriate error code to the client or logging the incident for further analysis.
From an operational perspective, this vulnerability results in a complete denial of service against the Sliver infrastructure. Since the panic is unhandled at the gRPC interceptor level, it causes the entire server process to exit immediately upon receipt of the malicious request. This means that all operators connected to the teamserver lose their connection instantly, halting any ongoing red team operations or defensive security activities dependent on the platform. The impact extends beyond mere service interruption; in active engagement scenarios, such a crash can lead to loss of situational awareness and potentially expose operational details if logs are not properly secured before termination. Furthermore, because the trigger requires control over an implant, this vulnerability is particularly dangerous as it leverages existing access granted through prior compromise to degrade or destroy the command infrastructure itself.
This issue aligns with CWE-20 Improper Input Validation, as the system fails to verify that incoming data meets expected length and format requirements before processing. Additionally, it relates to CWE-754 Improper Check for Unusual or Exceptional Conditions because the application does not handle edge cases such as empty or near-empty payloads correctly. In terms of attack tactics, this behavior corresponds to MITRE ATT&CK technique T1529 System Shutdown/Reboot, where an adversary disrupts availability by crashing critical systems. Although typically associated with active disruption rather than stealthy persistence, the ability to crash a C2 server represents a severe degradation of operational capability for security teams relying on continuous monitoring and control.
To mitigate this vulnerability, organizations running Sliver versions prior to 1.7.8 must upgrade immediately to the patched release where input validation has been strengthened within the BinaryMagic function and gRPC interceptors have been updated to recover from panics gracefully. Until an update is applied, operators should avoid using download functions through sessions that may be associated with untrusted or potentially compromised implants. Implementing network-level monitoring can also help detect anomalous traffic patterns indicative of this exploit attempt, although the primary defense remains applying the vendor-provided patch. Regular auditing of third-party dependencies and ensuring that vendored libraries are kept up to date is essential for maintaining resilience against similar input validation flaws in complex frameworks like Sliver.