CVE-2026-5773
Publication date 29 April 2026
Last updated 10 July 2026
Ubuntu priority
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.
Read the notes from the security team
Why is this CVE low priority?
curl is dropping support for SMB later in 2026 and only supports SMB version 1
Mitigation
Avoid using SMB
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| curl | 26.04 LTS resolute |
Fixed 8.18.0-1ubuntu2.1
|
| 24.04 LTS noble |
Fixed 8.5.0-2ubuntu10.9
|
|
| 22.04 LTS jammy |
Fixed 7.81.0-1ubuntu1.24
|
|
| 20.04 LTS focal |
Fixed 7.68.0-1ubuntu2.25+esm5
|
|
| 18.04 LTS bionic |
Fixed 7.58.0-2ubuntu3.24+esm10
|
|
| 16.04 LTS xenial |
Fixed 7.47.0-1ubuntu2.19+esm17
|
|
| 14.04 LTS trusty |
Not affected
|
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Severity score breakdown
CVSS version: CVSS v3.0
Base score
7.5 · High
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
References
Related Ubuntu Security Notices (USN)
- USN-8227-1
- curl vulnerabilities
- 4 May 2026
- USN-8525-1
- curl vulnerabilities
- 9 July 2026