{"schemaVersion":3,"id":"CVE-2026-103399","aliases":["UBUNTU-CVE-2026-103399","DEBIAN-CVE-2026-103399"],"status":"published","duplicateOf":null,"title":null,"description":"A flaw was found in SoupServer (libsoup). When an HTTP/1.x client sends a request with Expect: 100-continue and a request body, and SoupServer returns an early final (non-1xx) response before the body is read, the server neither drains the declared body bytes nor closes the connection. On a keep-alive connection, those leftover bytes are interpreted as a subsequent HTTP request. A remote, unauthenticated attacker can place a complete HTTP request in the body and cause SoupServer to process that smuggled request, leading to unintended request handling.","dates":{"published":"2026-09-30T17:42:31.307Z","modified":"2026-09-30T19:11:12.971Z","reserved":null,"kevAdded":[],"kevDue":[]},"cvss":{"headline":{"score":5.3,"severity":"medium","version":"3.1","versionLabel":"v3.1","source":"CVE.org","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","computed":false,"selection":"backend-summary"},"metrics":[{"version":"3.1","versionLabel":"v3.1","source":"CVE.org","score":5.3,"severity":"medium","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","exploitability":null,"impact":null,"computed":false},{"version":"3.1","versionLabel":"v3.1","source":"OSV · Ubuntu","score":5.3,"severity":"medium","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","exploitability":10,"impact":2.3,"computed":true},{"version":"3.1","versionLabel":"v3.1","source":"OSV · 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versions (No fix recorded)","eol":null,"hubHref":null}],"affectedCount":4,"eol":{"hasEol":false,"count":0},"references":[{"url":"https://access.redhat.com/security/cve/CVE-2026-103399","label":"access.redhat.com/security/cve/CVE-2026-103399","hostname":"access.redhat.com","tags":["VDB Entry","X Refsource REDHAT","REPORT"]},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2543949","label":"bugzilla.redhat.com/show_bug.cgi?id=2543949","hostname":"bugzilla.redhat.com","tags":["Issue Tracking","X Refsource REDHAT","REPORT"]},{"url":"https://ubuntu.com/security/CVE-2026-103399","label":"ubuntu.com/security/CVE-2026-103399","hostname":"ubuntu.com","tags":["REPORT"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-103399","label":"www.cve.org/CVERecord?id=CVE-2026-103399","hostname":"www.cve.org","tags":["REPORT"]},{"url":"https://gitlab.gnome.org/GNOME/libsoup/-/work_items/539","label":"gitlab.gnome.org/GNOME/libsoup/-/work_items/539","hostname":"gitlab.gnome.org","tags":["REPORT"]},{"url":"https://gitlab.gnome.org/GNOME/libsoup/-/merge_requests/560","label":"gitlab.gnome.org/GNOME/libsoup/-/merge_requests/560","hostname":"gitlab.gnome.org","tags":["REPORT"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-103399","label":"security-tracker.debian.org/tracker/CVE-2026-103399","hostname":"security-tracker.debian.org","tags":["Advisory"]}],"lineage":{"upstream":[],"downstream":["OPENSUSE-SU-2026:12132-1","SUSE-SU-2026:4690-1","SUSE-SU-2026:4703-1","SUSE-SU-2026:4739-1"],"duplicates":[],"related":["OPENSUSE-SU-2026:12132-1","SUSE-SU-2026:4690-1","SUSE-SU-2026:4703-1","SUSE-SU-2026:4739-1"]},"timeline":[{"kind":"published","date":"2026-09-30T17:42:31.307Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"modified","date":"2026-09-30T19:11:12.971Z","label":"Last modified","detail":"Vulnerability information updated.","source":null}],"risk":{"score":21,"level":"low","profile":"Default","thresholds":{"critical":75,"high":50,"medium":25,"low":10}},"meta":{"dataAsOf":"2026-10-22T05:31:49.363Z","stale":false,"partial":false}}