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Description

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.

PUBLISHED Reserved 2026-04-08 | Published 2026-05-13 | Updated 2026-05-13 | Assigner curl

Problem types

CWE-488 Exposure of Data Element to Wrong Session

Product status

Default status
unaffected

8.19.0 (semver)
affected

8.18.0 (semver)
affected

8.17.0 (semver)
affected

8.16.0 (semver)
affected

8.15.0 (semver)
affected

8.14.1 (semver)
affected

8.14.0 (semver)
affected

8.13.0 (semver)
affected

8.12.1 (semver)
affected

8.12.0 (semver)
affected

8.11.1 (semver)
affected

8.11.0 (semver)
affected

8.10.1 (semver)
affected

8.10.0 (semver)
affected

8.9.1 (semver)
affected

8.9.0 (semver)
affected

8.8.0 (semver)
affected

8.7.1 (semver)
affected

8.7.0 (semver)
affected

8.6.0 (semver)
affected

8.5.0 (semver)
affected

8.4.0 (semver)
affected

8.3.0 (semver)
affected

8.2.1 (semver)
affected

8.2.0 (semver)
affected

8.1.2 (semver)
affected

8.1.1 (semver)
affected

8.1.0 (semver)
affected

8.0.1 (semver)
affected

8.0.0 (semver)
affected

7.88.1 (semver)
affected

7.88.0 (semver)
affected

7.87.0 (semver)
affected

7.86.0 (semver)
affected

7.85.0 (semver)
affected

7.84.0 (semver)
affected

7.83.1 (semver)
affected

7.83.0 (semver)
affected

7.82.0 (semver)
affected

7.81.0 (semver)
affected

7.80.0 (semver)
affected

7.79.1 (semver)
affected

7.79.0 (semver)
affected

7.78.0 (semver)
affected

7.77.0 (semver)
affected

7.76.1 (semver)
affected

7.76.0 (semver)
affected

7.75.0 (semver)
affected

7.74.0 (semver)
affected

7.73.0 (semver)
affected

7.72.0 (semver)
affected

7.71.1 (semver)
affected

7.71.0 (semver)
affected

7.70.0 (semver)
affected

7.69.1 (semver)
affected

7.69.0 (semver)
affected

7.68.0 (semver)
affected

7.67.0 (semver)
affected

7.66.0 (semver)
affected

7.65.3 (semver)
affected

7.65.2 (semver)
affected

7.65.1 (semver)
affected

7.65.0 (semver)
affected

7.64.1 (semver)
affected

7.64.0 (semver)
affected

7.63.0 (semver)
affected

7.62.0 (semver)
affected

7.61.1 (semver)
affected

7.61.0 (semver)
affected

7.60.0 (semver)
affected

7.59.0 (semver)
affected

7.58.0 (semver)
affected

7.57.0 (semver)
affected

7.56.1 (semver)
affected

7.56.0 (semver)
affected

7.55.1 (semver)
affected

7.55.0 (semver)
affected

7.54.1 (semver)
affected

7.54.0 (semver)
affected

7.53.1 (semver)
affected

7.53.0 (semver)
affected

7.52.1 (semver)
affected

7.52.0 (semver)
affected

7.51.0 (semver)
affected

7.50.3 (semver)
affected

7.50.2 (semver)
affected

7.50.1 (semver)
affected

7.50.0 (semver)
affected

7.49.1 (semver)
affected

7.49.0 (semver)
affected

7.48.0 (semver)
affected

7.47.1 (semver)
affected

7.47.0 (semver)
affected

7.46.0 (semver)
affected

7.45.0 (semver)
affected

7.44.0 (semver)
affected

7.43.0 (semver)
affected

7.42.1 (semver)
affected

7.42.0 (semver)
affected

7.41.0 (semver)
affected

7.40.0 (semver)
affected

Credits

Osama Hamad finder

Daniel Stenberg remediation developer

References

www.openwall.com/lists/oss-security/2026/04/29/9

hackerone.com/reports/3650689 exploit

curl.se/docs/CVE-2026-5773.json (json)

curl.se/docs/CVE-2026-5773.html (www)

hackerone.com/reports/3650689 (issue)

cve.org (CVE-2026-5773)

nvd.nist.gov (CVE-2026-5773)

Download JSON