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.
02 / AFFECTED SOFTWARE
Affected packages
109 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
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.
05 / REFERENCES
Further evidence
- http://www.openwall.com/lists/oss-security/2026/04/29/9
- https://curl.se/docs/CVE-2026-5773.html
- https://curl.se/docs/CVE-2026-5773.json
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/5xxx/CVE-2026-5773.json
- https://hackerone.com/reports/3650689
- https://nvd.nist.gov/vuln/detail/CVE-2026-5773