CVE-2020-12651Public exploitNetwork attack vector

Code execution via wrapped CSI line index

Published May 15, 2020 · Updated Aug 4, 2024

Memory corruption in VanDyke SecureCRT before 8.7.2 allows remote attackers to execute code through a malicious terminal control sequence. CSI functions use an oversized line number in signed comparisons, causing it to wrap beyond INT_MAX and index outside the terminal's line-buffer array. A device must send a supported control sequence after a successful connection; the flaw also affects SecureCRT for iOS 2.3.1 and earlier, and vendor testing produced a crash.

CVSS severity9.8
Critical
EPSS probability6.60%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory corruption in VanDyke SecureCRT before 8.7.2 allows remote attackers to execute code through a malicious terminal control sequence. CSI functions use an oversized line number in signed comparisons, causing it to wrap beyond INT_MAX and index outside the terminal's line-buffer array. A device must send a supported control sequence after a successful connection; the flaw also affects SecureCRT for iOS 2.3.1 and earlier, and vendor testing produced a crash.

The record

CVE
CVE-2020-12651
Published
May 15, 2020
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-190, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 15, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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
10.0NIST NVDAV:N/AC:L/Au:N/C:C/I:C/A:C

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-190Integer Overflow or Wraparound
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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