CVE-2026-5773: wrong reuse of SMB connection
libcurl might in some circumstances reuse the wrong connection for SMB(S) transfers. libcurl features a pool of recent connections so that subsequent requests can reuse an existing connection to avoid overhead. When reusing a connection a range of criteria must be met. Due to a logical error in the code, a network transfer operation that was requested by an application could wrongfully reuse an existing SMB connection to the same server that was using a different 'share' than the new subsequent transfer should. This could in unlucky situations lead to the download of the wrong file or the upload of a file to the wrong place. When this happens, the same credentials are used and the server name is the same.
Affected Software
Remediation
Patch Available
Patch Available
Event History
Frequently Asked Questions
What is the severity of CVE-2026-5773?
CVE-2026-5773 has a medium severity rating due to the potential for unauthorized data access in SMB transfers.
How do I fix CVE-2026-5773?
To mitigate CVE-2026-5773, update libcurl to a version beyond 8.20.0, as this issue has been addressed in subsequent releases.
What impact does CVE-2026-5773 have on my system?
CVE-2026-5773 can lead to data being transferred over an incorrect SMB connection, potentially exposing sensitive information.
Is CVE-2026-5773 exploitable in all environments?
CVE-2026-5773 is primarily exploitable in environments using libcurl for SMB(S) transfers where connection reuse occurs.
What versions of libcurl are affected by CVE-2026-5773?
CVE-2026-5773 affects libcurl versions from 7.40.0 to 8.20.0 inclusive.