CVE-2023-39726Public exploitNetwork attack vector

Command execution via OSC 50 full echoback

Published Oct 26, 2023 · Updated Sep 10, 2024

Code injection in Mintty 3.6.4 and earlier allows remote attackers to execute commands through crafted OSC 50 terminal output. The OSC 50 font query returns a failed font name verbatim, echoing attacker-controlled bytes, including control characters, into the shell input stream. Exploitation requires attacker-controlled text to reach the terminal unescaped; successful echoback executes commands with the terminal user's privileges.

CVSS severity9.8
Critical
EPSS probability1.03%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Code injection in Mintty 3.6.4 and earlier allows remote attackers to execute commands through crafted OSC 50 terminal output. The OSC 50 font query returns a failed font name verbatim, echoing attacker-controlled bytes, including control characters, into the shell input stream. Exploitation requires attacker-controlled text to reach the terminal unescaped; successful echoback executes commands with the terminal user's privileges.

The record

CVE
CVE-2023-39726
Published
Oct 26, 2023
Updated
Sep 10, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-96, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 26, 2023CVE publishedPublication date reported by the CVE source.
  2. Sep 10, 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

9.8NIST NVDCVSS: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-96Improper Neutralization of Directives in Statically Saved Code ('Static Code Injection')
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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