Bug 2496768 (CVE-2026-12064) - CVE-2026-12064 curl: curl: SSH host verification bypass when using schemeless URLs with SFTP/SCP
Summary: CVE-2026-12064 curl: curl: SSH host verification bypass when using schemeless...
Keywords:
Status: NEW
Alias: CVE-2026-12064
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 2497523 2497524 2497526
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-07-03 07:02 UTC by OSIDB Bzimport
Modified: 2026-08-17 04:40 UTC (History)
8 users (show)

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

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System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2026:55450 0 None None None 2026-08-17 04:40:25 UTC

Description OSIDB Bzimport 2026-07-03 07:02:04 UTC 
When a user invokes curl using a schemeless URL combined with
`--proto-default` sftp (or scp), a disconnect occurs between the tool layer
and libcurl. The tool layer incorrectly infers the URL scheme, which
erroneously bypasses the initialization of critical SSH security options like
CURLOPT_SSH_HOST_PUBLIC_KEY_SHA256 and CURLOPT_SSH_KNOWNHOSTS. Conversely, the
libcurl runtime successfully honors CURLOPT_DEFAULT_PROTOCOL and establishes
the connection via SFTP/SCP as specified. Because the tool layer skipped the
security configuration, these SSH host verification options are silently
omitted, causing curl to connect to an unverified SSH remote host without
throwing an error.
Comment 2 errata-xmlrpc 2026-08-17 04:40:24 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2026:55450 https://access.redhat.com/errata/RHSA-2026:55450
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