Vulnerability · Published Oct 13, 2026 · Assigned by GitHub_M
CVE-2026-54700ConnectBot SSH: Unbounded SSH field lengths can cause excessive memory allocation
Medium 6.9
In plain English
A medium-severity improper input validation in cbssh from connectbot. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 31% of all known vulnerabilities).
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Maven | org.connectbot.sshlib:sshlib | no fix listed | GHSA-ch3q-cw5r-f4hg |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| connectbot | cbssh | < 0.3.1 |
Weakness: CWE-20, CWE-789 · Vector: 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
References
- https://github.com/connectbot/cbssh/security/advisories/GHSA-ch3q-cw5r-f4hg x_refsource_CONFIRM
- https://github.com/connectbot/cbssh/pull/194 x_refsource_MISC
- https://github.com/connectbot/cbssh/commit/a08421fbe7cf8b72fa60fb8b2f98fb465dc43fd9 x_refsource_MISC
- https://github.com/connectbot/cbssh/releases/tag/v0.3.1 x_refsource_MISC