CVE-2023-34758Public exploitNetwork attack vector

Code execution via recoverable KEM session keys

Published Aug 28, 2023 · Updated Oct 2, 2024

Cryptographic failure in Bishop Fox Sliver 1.5.0 through 1.5.39 allows man-in-the-middle attackers to execute code on implants. The Sliver Key Encapsulation Mechanism derives a reusable shared secret from the server public key and implant private key embedded in each implant, allowing recovery of session keys and forgery of encrypted command-and-control messages. Exploitation requires interception of an HTTP or DNS implant channel and a copy of the corresponding implant binary; mTLS and WireGuard transports are not affected.

CVSS severity8.1
High
EPSS probability0.59%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cryptographic failure in Bishop Fox Sliver 1.5.0 through 1.5.39 allows man-in-the-middle attackers to execute code on implants. The Sliver Key Encapsulation Mechanism derives a reusable shared secret from the server public key and implant private key embedded in each implant, allowing recovery of session keys and forgery of encrypted command-and-control messages. Exploitation requires interception of an HTTP or DNS implant channel and a copy of the corresponding implant binary; mTLS and WireGuard transports are not affected.

The record

CVE
CVE-2023-34758
Published
Aug 28, 2023
Updated
Oct 2, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-327, T1557
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 28, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 2, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

8.1NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
9.2GitHubCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-327Use of a Broken or Risky Cryptographic Algorithm
T1557Adversary-in-the-Middle

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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