CVE-2025-27093

Sliver is a command and control framework that uses a custom Wireguard netstack. In versions 1.5.43 and earlier, and in development version 1.6.0-dev, the netstack does not limit traffic between Wireguard clients. This allows clients to communicate with each other unrestrictedly, potentially enabling leaked or recovered keypairs to be used to attack operators or allowing port forwardings to be accessible from other implants.

Sliver is a command and control framework that uses a custom Wireguard netstack. In versions 1.5.43 and earlier, and in development version 1.6.0-dev, the netstack does not limit traffic between Wireguard clients. This allows clients to communicate with each other unrestrictedly, potentially enabling leaked or recovered keypairs to be used to attack operators or allowing port forwardings to be accessible from other implants.

Summary

Sliver's custom Wireguard netstack doesn't limit traffic between Wireguard clients, this could lead to:

1. Leaked/recovered keypair (from a beacon) being used to attack operators.
2. Port forwardings usable from other implants.

Details

1. Sliver treat operators' Wireguard config and beacon/session's Wireguard config equally, they both connect to the wireguard listener created from the CLI.

2. The current netstack implementation does not filter traffic between clients. I think this piece of code handle traffic between clients, from experimental results clients can ping and connect to each other freely, and I didn't see any filtering here either:

File: server\c2\wireguard.go
246: func socketWGWriteEnvelope(connection net.Conn, envelope *sliverpb.Envelope) error {
247: 	data, err := proto.Marshal(envelope)
248: 	if err != nil {
249: 		wgLog.Errorf("Envelope marshaling error: %v", err)
250: 		return err
251: 	}
252: 	dataLengthBuf := new(bytes.Buffer)
253: 	binary.Write(dataLengthBuf, binary.LittleEndian, uint32(len(data)))
254: 	connection.Write(dataLengthBuf.Bytes())
255: 	connection.Write(data)
256: 	return nil
257: }
258: 

3. The docs says to use a Wireguard clients and operator wg-config to connect to the same WG listener as beacons: https://sliver.sh/docs?name=Port%20Forwarding

4. If the operator uses official wireguard clients that integrates with the OS's netstack (I'm using the Windows client) then their services are accessible on the wireguard interface's IP address (for example 100.64.0.3) when the services listen on 0.0.0.0 (SSH, RDP, SMB, etc)

5. The beacon's wireguard private key can be recovered through a process dump or other forensic techniques.

6. When a private key is recovered, an attacker can connect to 100.64.0.1:1337 (key exchange listener) to generate new wireguard clients without the operators' knowledge, in that way achieve persistence inside the wireguard network.

PoC

Easy way:

1. Create 2 operators wireguard config.
2. Connect them both to the wireguard listener.
3. From one machine, ping/scan/connect to the other's services like RDP (3389), SSH (22), etc.

Slightly complicated way:

1. From the operator's machine, connect to the wireguard listener.

2. On the attacker's machine, run a beacon.

3. Dump the process

4. Find the private key, public key, endpoint, etc in the dump file:

5. Construct a valid Wireguard config based on the strings found. On the attacker's machine, connect to the Wireguard listener.

6. Ping/scan/connect to the other's services like RDP (3389), SSH (22), etc.

Impact

The operator's machine is impacted, if their services contain a vulnerability, an attacker can exploit it and gain RCE. If not then it could be used to gather information (Hostname, SSH signature, etc).

Suggestion

1. Filter traffic between clients with a default-deny policy.
2. Differentiate between operators and beacons' wireguard config/client
3. Only allow specific one-way traffic when the operator request to open a Wireguard port forward.

Vulnerable versions

All versions containing wireguard functionality.

Sliver is a command and control framework that uses a custom Wireguard netstack. In versions 1.5.43 and earlier, and in development version 1.6.0-dev, the netstack does not limit traffic between Wireguard clients. This allows clients to communicate with each other unrestrictedly, potentially enabling leaked or recovered keypairs to be used to attack operators or allowing port forwardings to be accessible from other implants.

Sliver is a command and control framework that uses a custom Wireguard netstack. In versions 1.5.43 and earlier, and in development version 1.6.0-dev, the netstack does not limit traffic between Wireguard clients. This allows clients to communicate with each other unrestrictedly, potentially enabling leaked or recovered keypairs to be used to attack operators or allowing port forwardings to be accessible from other implants.

Summary

Sliver's custom Wireguard netstack doesn't limit traffic between Wireguard clients, this could lead to:

1. Leaked/recovered keypair (from a beacon) being used to attack operators.
2. Port forwardings usable from other implants.

Details

1. Sliver treat operators' Wireguard config and beacon/session's Wireguard config equally, they both connect to the wireguard listener created from the CLI.

2. The current netstack implementation does not filter traffic between clients. I think this piece of code handle traffic between clients, from experimental results clients can ping and connect to each other freely, and I didn't see any filtering here either:

File: server\c2\wireguard.go
246: func socketWGWriteEnvelope(connection net.Conn, envelope *sliverpb.Envelope) error {
247: 	data, err := proto.Marshal(envelope)
248: 	if err != nil {
249: 		wgLog.Errorf("Envelope marshaling error: %v", err)
250: 		return err
251: 	}
252: 	dataLengthBuf := new(bytes.Buffer)
253: 	binary.Write(dataLengthBuf, binary.LittleEndian, uint32(len(data)))
254: 	connection.Write(dataLengthBuf.Bytes())
255: 	connection.Write(data)
256: 	return nil
257: }
258: 

3. The docs says to use a Wireguard clients and operator wg-config to connect to the same WG listener as beacons: https://sliver.sh/docs?name=Port%20Forwarding

4. If the operator uses official wireguard clients that integrates with the OS's netstack (I'm using the Windows client) then their services are accessible on the wireguard interface's IP address (for example 100.64.0.3) when the services listen on 0.0.0.0 (SSH, RDP, SMB, etc)

5. The beacon's wireguard private key can be recovered through a process dump or other forensic techniques.

6. When a private key is recovered, an attacker can connect to 100.64.0.1:1337 (key exchange listener) to generate new wireguard clients without the operators' knowledge, in that way achieve persistence inside the wireguard network.

PoC

Easy way:

1. Create 2 operators wireguard config.
2. Connect them both to the wireguard listener.
3. From one machine, ping/scan/connect to the other's services like RDP (3389), SSH (22), etc.

Slightly complicated way:

1. From the operator's machine, connect to the wireguard listener.

2. On the attacker's machine, run a beacon.

3. Dump the process

4. Find the private key, public key, endpoint, etc in the dump file:

5. Construct a valid Wireguard config based on the strings found. On the attacker's machine, connect to the Wireguard listener.

6. Ping/scan/connect to the other's services like RDP (3389), SSH (22), etc.

Impact

The operator's machine is impacted, if their services contain a vulnerability, an attacker can exploit it and gain RCE. If not then it could be used to gather information (Hostname, SSH signature, etc).

Suggestion

1. Filter traffic between clients with a default-deny policy.
2. Differentiate between operators and beacons' wireguard config/client
3. Only allow specific one-way traffic when the operator request to open a Wireguard port forward.

Vulnerable versions

All versions containing wireguard functionality.

Silver has unrestricted traffic between Wireguard clients in github.com/bishopfox/sliver

These are all security issues fixed in the govulncheck-vulndb-0.0.20251105T184115-1.1 package on the GA media of openSUSE Tumbleweed.

This update for govulncheck-vulndb fixes the following issues:

• Update to version 0.0.20260723T184607 2026-07-23T18:46:07Z (jsc#PED-11136).

Go CVE Numbering Authority IDs added or updated with aliases:

• GO-2026-4730 CVE-2026-33022 GHSA-cv4x-93xx-wgfj
• GO-2026-4761 CVE-2026-33211 GHSA-j5q5-j9gm-2w5c
• GO-2026-5102 CVE-2026-45021 GHSA-3vcp-chfh-f6r2
• GO-2026-5272 CVE-2026-40938 GHSA-94jr-7pqp-xhcq
• GO-2026-5486 CVE-2026-40924 GHSA-m2cx-gpqf-qf74
• GO-2026-5542 CVE-2026-40090 GHSA-pj97-4p9w-gx3q
• GO-2026-5630 CVE-2026-25542 GHSA-rmx9-2pp3-xhcr
• GO-2026-5643 CVE-2026-40923 GHSA-rx35-6rhx-7858
• GO-2026-5675 CVE-2026-41492 GHSA-vvf7-6rmr-m29q
• GO-2026-5711 CVE-2026-40161 GHSA-wjxp-xrpv-xpff
• GO-2026-5746 CVE-2026-41567 GHSA-x86f-5xw2-fm2r
• GO-2026-5749 CVE-2026-41328 GHSA-x92x-px7w-4gx4
• GO-2026-5837 CVE-2026-44840 GHSA-q2m9-6jp9-c6mc
• GO-2026-5929 CVE-2026-44342 GHSA-26v7-h57m-gh9m
• GO-2026-5930 CVE-2026-33655 GHSA-6qcr-qxgr-m7fv
• GO-2026-5933 GHSA-3g4q-2f67-2gvh
• GO-2026-5934 GHSA-59qp-cfj3-rp64
• GO-2026-5935 GHSA-7856-g3gv-9wq8
• GO-2026-5936 CVE-2026-53552 GHSA-26rh-24rg-j3vv
• GO-2026-5937 CVE-2026-53508 GHSA-2jcc-mxv7-p3f9
• GO-2026-5938 CVE-2026-53553 GHSA-4g5x-hcwm-82jw
• GO-2026-5939 CVE-2026-10517 GHSA-698x-9w2p-7vvp
• GO-2026-5940 CVE-2026-53572 GHSA-6w3m-4hhp-775q
• GO-2026-5941 CVE-2026-53487 GHSA-gvhc-wv3v-7pf8
• GO-2026-5942 CVE-2026-46600
• GO-2026-5944 CVE-2026-50197 GHSA-659f-rgp5-w4wf
• GO-2026-5945 CVE-2026-6815 GHSA-rmxx-v9rj-vpvg
• GO-2026-5946 CVE-2026-52831 GHSA-v5px-423j-pf7p
• GO-2026-5947 CVE-2026-53649 GHSA-xqhv-chqm-fhcc
• GO-2026-5948 CVE-2026-50554 GHSA-588f-fvcv-xhvf
• GO-2026-5949 CVE-2026-50553 GHSA-rqrh-8wpv-x7hh
• GO-2026-5950 CVE-2026-53602 GHSA-339v-266x-79xr
• GO-2026-5951 CVE-2026-10219 GHSA-6jm8-4fhr-5w64
• GO-2026-5952 CVE-2026-49834 GHSA-9vcr-p3rj-q5q6
• GO-2026-5953 CVE-2026-9094 GHSA-c9w5-qp6m-m395
• GO-2026-5956 CVE-2026-55252 GHSA-h5g6-xmh4-hc37
• GO-2026-5957 CVE-2026-54158 GHSA-5xfx-xj4h-5p7r
• GO-2026-5958 CVE-2026-54068 GHSA-gcm7-57gf-953c
• GO-2026-5959 CVE-2026-54072 GHSA-h29v-hj44-q8cv
• GO-2026-5961 CVE-2026-54069 GHSA-hvr9-72v2-fff3
• GO-2026-5962 CVE-2026-54088 GHSA-m93h-4hw7-5qcm
• GO-2026-5963 CVE-2026-54067 GHSA-mvjr-vv3c-w4qv
• GO-2026-5964 CVE-2026-54066 GHSA-p4m3-mgmm-c664
• GO-2026-5965 CVE-2026-54070 GHSA-w7cg-whh7-xp28
• GO-2026-5966 CVE-2026-54089 GHSA-xqp3-jq6g-x3qm
• GO-2026-5967 CVE-2026-50551 GHSA-56mp-4f3v-fgj2
• GO-2026-5968 CVE-2026-54174 GHSA-fpg8-7664-jc5q
• GO-2026-5969 GHSA-g936-7jqj-mwv8
• GO-2026-5970 CVE-2026-56852
• GO-2026-5973 CVE-2026-54250 GHSA-jxr7-mqhw-9p98
• GO-2026-5974 CVE-2026-44300 GHSA-wmj8-9953-vff5
• GO-2026-5975 CVE-2026-50018 GHSA-42j2-w334-qxw7
• GO-2026-5976 CVE-2026-50141 GHSA-g7mm-9vx7-jm7h
• GO-2026-5977 CVE-2026-50013 GHSA-qrh4-p6v4-mrfg
• GO-2026-5978 CVE-2026-50125 GHSA-qw5r-ppcg-f8rj
• GO-2026-5979 CVE-2026-50006 GHSA-xrcf-6jh3-ggvx
• GO-2026-5980 CVE-2026-50158 GHSA-2c7f-fxww-6w6c
• GO-2026-5981 GHSA-mqxv-9rm6-w8qc
• GO-2026-5982 GHSA-pqg7-v6wh-3pfp
• GO-2026-5984 CVE-2026-53604 GHSA-2p2f-px33-4vv5
• GO-2026-5985 GHSA-7rx3-5wx3-5v76
• GO-2026-5986 CVE-2026-61699 GHSA-cm26-5974-52h8
• GO-2026-5987 CVE-2026-55513 GHSA-g4x6-jcvr-9m3g
• GO-2026-5988 CVE-2026-54628 GHSA-hwrq-8wxh-q4xv
• GO-2026-5989 CVE-2026-55512 GHSA-m3cx-mwpg-32jg
• GO-2026-5990 CVE-2026-54629 GHSA-mf78-3rpf-r784
• GO-2026-5991 CVE-2026-53603 GHSA-q4vm-pq3q-8wgq
• GO-2026-5992 CVE-2026-61549 GHSA-qf34-295c-26v8
• GO-2026-5996 CVE-2026-54450 GHSA-pph6-vfjv-vpjw
• GO-2026-5997 CVE-2026-54452 GHSA-xgch-x3mx-cm3c
• GO-2026-5998 CVE-2026-54495 GHSA-398h-7f66-3h4p
• GO-2026-5999 CVE-2026-10814 GHSA-jh6h-v6mp-h22v
• GO-2026-6002 CVE-2026-58196 GHSA-pr64-jmmf-jp54
• GO-2026-6003 CVE-2026-53714 GHSA-22xc-xg2r-9j7v
• GO-2026-6004 CVE-2026-52833 GHSA-3v79-m2cg-89ww
• GO-2026-6005 CVE-2026-53715 GHSA-8fv2-88gg-hm7q
• GO-2026-6006 CVE-2026-53716 GHSA-cxpq-8v7q-cg56 *…