Cyber Resilience

CVE-2026-32941

DoS in Bishopfox Sliver ≤ 1.7.3

Public PoCDoS
Published
20 March 2026
Modified
24 March 2026
Patch / advisory
CVSS Score v4 7.1
Click a component to see what it means
Raw vectorCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0030 22th percentile
Risk Priority 35 floored blend · peak EPSS

Summary

CVE-2026-32941 is a high-severity Allocation of Resources Without Limits or Throttling (CWE-770) vulnerability in Bishopfox Sliver. Its CVSS base score is 7.1 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Network Denial of Service (T1498); ranked at the 22th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to AC-10 (Concurrent Session Control) and SC-6 (Resource Availability) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

Sliver is a command and control framework that uses a custom Wireguard netstack. Versions 1.7.3 and below contain a Remote OOM (Out-of-Memory) vulnerability in the Sliver C2 server's mTLS and WireGuard C2 transport layer. The socketReadEnvelope and socketWGReadEnvelope functions trust…

more

an attacker-controlled 4-byte length prefix to allocate memory, with ServerMaxMessageSize allowing single allocations of up to ~2 GiB. A compromised implant or an attacker with valid credentials can exploit this by sending fabricated length prefixes over concurrent yamux streams (up to 128 per connection), forcing the server to attempt allocating ~256 GiB of memory and triggering an OS OOM kill. This crashes the Sliver server, disrupts all active implant sessions, and may degrade or kill other processes sharing the same host. The same pattern also affects all implant-side readers, which have no upper-bound check at all. The issue was not fixed at the the time of publication.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1498 Network Denial of Service Impact
Adversaries may perform Network Denial of Service (DoS) attacks to degrade or block the availability of targeted resources to users.
T1499 Endpoint Denial of Service Impact
Adversaries may perform Endpoint Denial of Service (DoS) attacks to degrade or block the availability of services to users.
T1499.003 Application Exhaustion Flood Impact
Adversaries may target resource intensive features of applications to cause a denial of service (DoS), denying availability to those applications.
T1498.001 Direct Network Flood Impact
Adversaries may attempt to cause a denial of service (DoS) by directly sending a high-volume of network traffic to a target.
T1498.002 Reflection Amplification Impact
Adversaries may attempt to cause a denial of service (DoS) by reflecting a high-volume of network traffic to a target.
T1499.001 OS Exhaustion Flood Impact
Adversaries may launch a denial of service (DoS) attack targeting an endpoint's operating system (OS).
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-25791Same product: Bishopfox Sliver
CVE-2026-29781Same product: Bishopfox Sliver
CVE-2025-27090Same product: Bishopfox Sliver
CVE-2026-34227Same product: Bishopfox Sliver
CVE-2026-25760Same product: Bishopfox Sliver
CVE-2023-34758Same product: Bishopfox Sliver
CVE-2024-41761Shared CWE-770, CWE-789
CVE-2026-42440Shared CWE-770, CWE-789
CVE-2024-41132Shared CWE-770, CWE-789
CVE-2026-25899Shared CWE-770, CWE-789

Affected Assets

bishopfox
sliver
≤ 1.7.3

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 5 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V15.4.4

Mitigating Controls (NIST 800-53 r5) AI

Directly enforces a hard limit on concurrent sessions, structurally preventing unbounded resource allocation.

Requires explicit allocation of resources by priority or quota, directly stopping unlimited allocation.

Input validation directly rejects or bounds untrusted size values before any allocation occurs.

Imposes a limit on consecutive invalid attempts, preventing one specific class of unbounded resource consumption.

Reduces impact of resulting DoS events without preventing the underlying lack of allocation limits.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.IR-04 mostly match
degrades

Monitoring capacity and taking action to maintain availability directly reduces unchecked resource allocation.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly prevent coding flaws that trust unvalidated size values for allocations.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Baseline comparison of CPU, memory and bandwidth usage helps surface uncontrolled resource allocations before they cause service degradation.

finds

Security testing in development can detect and block excessive allocation flaws before deployment.

prevents

Capacity projections and elasticity measures ensure that allocation requests are bounded and can be throttled, reducing the window in which an attacker can force unbounded resource reservations.

mitigates

Defining retention periods and deletion schedules for backup copies prevents indefinite accumulation of data on storage media without corresponding resource-management controls.

mitigates

Architectural redundancy and automatic failover limit the impact of an attacker who forces excessive allocations, because spare capacity can absorb the load until the primary instance recovers.

prevents

Secure development lifecycle includes input validation and size checks that prevent unbounded allocations.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Oracle Linux 8 (2 rules)
  • V-248552 OL 8 must be configured so that all network connections associated with SSH traffic terminate after becoming unresponsive. prevents CWE-770
  • V-248553 OL 8 must be configured so that all network connections associated with SSH traffic are terminated after 10 minutes of becoming unresponsive. prevents CWE-770
Oracle Linux 9 (2 rules)
  • V-271710 OL 9 must be configured so that all network connections associated with SSH traffic are terminated after 10 minutes of becoming unresponsive. prevents CWE-770
  • V-271709 OL 9 must be configured so that all network connections associated with SSH traffic terminate after becoming unresponsive. prevents CWE-770
RHEL 8 (1 rule)
  • V-230244 RHEL 8 must be configured so that all network connections associated with SSH traffic terminate after becoming unresponsive. prevents CWE-770

References