CVE-2023-38408Public exploitNetwork attack vector

Remote code execution via unsafe PKCS#11 loading

Published Jul 20, 2023 · Updated Oct 15, 2024

Remote code execution in OpenSSH ssh-agent 5.5 through 9.3p1 allows remote attackers to execute code through a forwarded agent socket. PKCS#11 requests make ssh-pkcs11-helper load and unload allowlisted /usr/lib libraries whose constructors, destructors, and loader side effects can be chained. The victim must forward the agent to an attacker-controlled system, PKCS#11 support must be enabled, and exploitable libraries must be present.

CVSS severity9.8
Critical
EPSS probability79.70%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Remote code execution in OpenSSH ssh-agent 5.5 through 9.3p1 allows remote attackers to execute code through a forwarded agent socket. PKCS#11 requests make ssh-pkcs11-helper load and unload allowlisted /usr/lib libraries whose constructors, destructors, and loader side effects can be chained. The victim must forward the agent to an attacker-controlled system, PKCS#11 support must be enabled, and exploitable libraries must be present.

The record

CVE
CVE-2023-38408
Published
Jul 20, 2023
Updated
Oct 15, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-428, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 20, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 15, 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

9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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-428Unquoted Search Path or Element
T1203Exploitation for Client Execution

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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