CVE-2026-54700
6.9MediumPublished 13 Oct 2026 · NVD status: Deferred · AI triage by gemini-3.8-flash
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Active
- Impact
- High impact on availability
- Weakness
- CWE-20, CWE-789
Impact
A malicious or compromised SSH server can crash client applications using this library via an unhandled OutOfMemoryError. An attacker only needs the client to initiate an SSH connection to their server, with no credentials required.
Root cause
The protocol parser blindly trusts inner byte lengths and element counts declared in packets without checking whether they exceed the actual containing packet boundaries.
Affected systems
ConnectBot SSH Client Library (cbssh) prior to 0.3.1
CVSS v4.0 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Fix & remediation
Upgrade the ConnectBot SSH Client Library dependency to version 0.3.1 or later. If updating immediately is not possible, avoid connecting to untrusted SSH servers and disable SSH agent forwarding.
AI-suggested. Run it in staging first and check it against the vendor advisory. Why?
NVD description
ConnectBot SSH Client Library is written in Kotlin with Kaitai Struct and KStateMachine. Prior to 0.3.1, the SSH protocol parser trusts attacker-controlled inner byte lengths and element counts without verifying that they fit in the containing packet. A malicious or compromised SSH server can return a small malformed packet whose oversized declarations cause the Kaitai Struct Java runtime to attempt excessive allocation or repeated parsing before detecting truncated input. The general transport path requires a client connection but no authentication or optional feature; malformed SSH-agent messages additionally require SSH agent forwarding. The issue can raise an uncaught OutOfMemoryError and terminate the application process, with no demonstrated confidentiality or integrity impact. This issue is fixed in version 0.3.1.