Bug 2530645 - CVE-2026-56855 complyctl: golang.org/x/crypto/ssh: Denial of Service via crafted messages [fedora-all]
Summary: CVE-2026-56855 complyctl: golang.org/x/crypto/ssh: Denial of Service via craf...
Keywords:
Status: NEW
Alias: None
Product: Fedora
Classification: Fedora
Component: complyctl
Version: rawhide
Hardware: Unspecified
OS: Unspecified
medium
medium
Target Milestone: ---
Assignee: Marcus Burghardt
QA Contact:
URL:
Whiteboard: {"flaws": ["6149aca5-d0d4-472f-b5bb-7...
Depends On:
Blocks: CVE-2026-56855
TreeView+ depends on / blocked
 
Reported: 2026-09-09 09:46 UTC by jkelly
Modified: 2026-09-10 11:10 UTC (History)
3 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Type: ---
Embargoed:


Attachments (Terms of Use)

Description jkelly 2026-09-09 09:46:03 UTC
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

Previously, after a channel has been established, a malicious peer could send crafted messages that would deadlock the entire connection. Now, we handle all RFC 4254 channel messages; global requests are handled explicitly. Then, treat all other messages as a protocol error and tear the connection down instead of buffering and blocking.

Comment 1 Marcus Burghardt 2026-09-10 11:10:54 UTC
complyctl vendors golang.org/x/crypto v0.55.0 as an indirect dependency (via go-securesystemslib in the Sigstore verification stack). However, the only usage of golang.org/x/crypto/ssh in the entire dependency graph is ssh.NewPublicKey() and ssh.FingerprintSHA256() for DSSE key fingerprinting (go-securesystemslib/dsse/verify.go). The vulnerable symbols (Dial, NewClientConn, NewControlClientConn, NewServerConn) are never called — complyctl does not establish SSH connections. The flaw is therefore not exploitable in complyctl. We will bump golang.org/x/crypto to >= v0.56.0 in a forthcoming dependency update to clear the scanner finding.


Note You need to log in before you can comment on or make changes to this bug.