CVE-2026-5773

Name	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.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
curl (PTS)	bullseye	7.74.0-1.3+deb11u13	vulnerable
	bullseye (security)	7.74.0-1.3+deb11u16	vulnerable
	bookworm	7.88.1-10+deb12u14	vulnerable
	bookworm (security)	7.88.1-10+deb12u5	vulnerable
	trixie	8.14.1-2+deb13u3	vulnerable
	forky	8.20.0-1	fixed
	sid	8.20.0-2	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
curl	source	(unstable)	8.20.0~rc2-1

Notes

[trixie] - curl <no-dsa> (Minor issue)
[bookworm] - curl <no-dsa> (Minor issue)
[bullseye] - curl <postponed> (Minor issue; can be fixed in next update)
https://curl.se/docs/CVE-2026-5773.html
Introduced by: https://github.com/curl/curl/commit/aec2e865f06669b9cb5d26cc1148d70bc418b163 (curl-7_40_0)
Fixed by: https://github.com/curl/curl/commit/74a169575d6412dc0ff532acdf94de35a6c2a571 (rc-8_20_0-2)