BishopFox Sliver up to 1.7.3 allocation of resources

Summaryinfo

A vulnerability classified as problematic was found in BishopFox Sliver up to 1.7.3. This affects an unknown part. Such manipulation leads to allocation of resources. This vulnerability is listed as CVE-2026-32941. The attack may be performed from remote. There is no available exploit.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in BishopFox Sliver up to 1.7.3. Affected by this issue is an unknown function. The manipulation with an unknown input leads to a allocation of resources vulnerability. Using CWE to declare the problem leads to CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. Impacted is availability. CVE summarizes:

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 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.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-32941 since 03/17/2026. The exploitation is known to be easy. The attack may be launched remotely. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1499.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Vendor

• BishopFox

Name

• Sliver

Version

• 1.7.0
• 1.7.1
• 1.7.2
• 1.7.3

Website

• Product: https://github.com/BishopFox/sliver/

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