CVE-2026-54700Network attack vector

Application crash via unchecked SSH field lengths

Published Oct 13, 2026 · Updated Oct 13, 2026

Memory exhaustion in ConnectBot cbssh before 0.3.1 allows remote attackers to crash client applications via malformed SSH packets. Its Kaitai byte-string parser allocates from untrusted inner lengths before checking available bytes, while unchecked element counts trigger excessive repeated parsing. A client must connect to a malicious or compromised SSH server without any authentication requirement; the additional agent-message path requires agent forwarding, and no confidentiality or integrity impact is demonstrated.

CVSS severity6.9
Medium
EPSS probability0.37%
Next 30 days · Oct 18, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory exhaustion in ConnectBot cbssh before 0.3.1 allows remote attackers to crash client applications via malformed SSH packets. Its Kaitai byte-string parser allocates from untrusted inner lengths before checking available bytes, while unchecked element counts trigger excessive repeated parsing. A client must connect to a malicious or compromised SSH server without any authentication requirement; the additional agent-message path requires agent forwarding, and no confidentiality or integrity impact is demonstrated.

The record

CVE
CVE-2026-54700
Published
Oct 13, 2026
Updated
Oct 13, 2026
Vendor
ConnectBot
Product
cbssh
Classifications
CWE-20, CWE-789, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 13, 2026CVE publishedPublication date reported by the CVE source.
  2. Oct 13, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 0.3.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ConnectBot · cbsshversion=< 0.3.1

Published CVSS scores

6.9GitHub CNACVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/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.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
CWE-789Memory Allocation with Excessive Size Value
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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