CVE-2026-5773
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.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
| OS | Version | Status | Fixed in |
|---|---|---|---|
| debian | bookworm | affected | |
| debian | bullseye | affected | |
| debian | forky | fixed | 8.20.0~rc2-1 |
| debian | sid | fixed | 8.20.0~rc2-1 |
| debian | trixie | affected | |
| sles | affected | | |
| windows | affected | |
References
- https://curl.se/docs/CVE-2026-5773.html
- https://curl.se/docs/CVE-2026-5773.json
- https://hackerone.com/reports/3650689
- http://www.openwall.com/lists/oss-security/2026/04/29/9
- https://security-tracker.debian.org/tracker/CVE-2026-5773
- https://www.suse.com/security/cve/CVE-2026-5773.html
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-5773
CWEs
CWE-918
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.