Allocation of Resources Without Limits or Throttling Affecting golang.org/x/crypto/ssh package, versions <0.56.0
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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- published3 Sept 2026
- disclosed2 Sept 2026
- creditWill Mortensen
Introduced: 2 Sep 2026
NewCVE-2026-56855 Â (opens in a new tab)How to fix?
Upgrade golang.org/x/crypto/ssh to version 0.56.0 or higher.
Overview
golang.org/x/crypto/ssh is a SSH client and server
Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling in its connection multiplexing, reached through Dial, NewClientConn, NewControlClientConn, and NewServerConn, which buffers unhandled messages that fall outside the RFC 4254 channel and global-request handling instead of treating them as protocol errors. A malicious peer can deadlock the entire SSH connection by sending unexpected messages once a channel has been established. This requires a completed handshake and an open SSH channel with the attacker as the peer.