{"id":"CVE-2026-120831","aliases":["AZL-112682","DEBIAN-CVE-2026-120831","EUVD-2026-115656","GHSA-c4qr-qpmh-whrf","UBUNTU-CVE-2026-120831"],"status":"published","title":"Libslirp: libslirp: queue pointer corruption in if_output() leading to denial of service","description":"A flaw was found in libslirp in if_output(). When moving a session from the fast queue to the batch queue, the code unlinked and reinserted an arbitrary packet via ifm-\u003em_nextpkt instead of the session queue head, corrupting queue pointers. A guest generating burst traffic could crash the host networking process, causing a denial of service.","severity":{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.00265,"percentile":0.18627,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-787"],"published":"2026-11-03T01:55:20Z","modified":"2026-11-05T14:17:04Z","affected":[{"source":"osv","ecosystem":"Azure Linux:3","package":"libslirp","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"4.9.6-1"}]}]},{"source":"osv","ecosystem":"Debian:12","package":"libslirp","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.7.0-1","4.8.0-1","4.9.1-1","4.9.2-1","4.9.3-1","4.9.4-1","4.9.5-1"]},{"source":"osv","ecosystem":"Debian:13","package":"libslirp","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.8.0-1","4.8.0-1+deb13u1","4.9.1-1","4.9.2-1","4.9.3-1","4.9.4-1","4.9.5-1"]},{"source":"osv","ecosystem":"Debian:14","package":"libslirp","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.8.0-1","4.9.1-1","4.9.2-1","4.9.3-1","4.9.4-1","4.9.5-1"]},{"source":"osv","ecosystem":"Ubuntu:20.04:LTS","package":"libslirp","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.0.0-1","4.0.0-2","4.1.0-1","4.1.0-2","4.1.0-2ubuntu1","4.1.0-2ubuntu2","4.1.0-2ubuntu2.1","4.1.0-2ubuntu2.2"]},{"source":"osv","ecosystem":"Ubuntu:22.04:LTS","package":"libslirp","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.4.0-1build1","4.6.1-1","4.6.1-1build1","4.6.1-1ubuntu0.2"]},{"source":"osv","ecosystem":"Ubuntu:24.04:LTS","package":"libslirp","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.7.0-1ubuntu1","4.7.0-1ubuntu2","4.7.0-1ubuntu3","4.7.0-1ubuntu3.1"]},{"source":"osv","ecosystem":"Ubuntu:26.10","package":"libslirp","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.9.1-1ubuntu1","4.9.3-1ubuntu1"]},{"source":"osv","ecosystem":"Ubuntu:26.04:LTS","package":"libslirp","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.8.0-1ubuntu1","4.9.1-1ubuntu1","4.9.1-1ubuntu1.1"]}],"products":[{"vendor":"red hat","product":"red hat enterprise linux 10"},{"vendor":"red hat","product":"red hat enterprise linux 8"},{"vendor":"red hat","product":"red hat enterprise linux 9"},{"vendor":"red hat","product":"red hat openshift container platform 4"},{"vendor":"red hat","product":"red hat openshift container platform 5"}],"references":[{"url":"https://access.redhat.com/security/cve/CVE-2026-120831","tags":["vdb-entry","x_refsource_REDHAT","advisory","report"]},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2565425","tags":["issue-tracking","x_refsource_REDHAT","report"]},{"url":"https://gitlab.freedesktop.org/slirp/libslirp/-/commit/bad35bd3b529dc47aa109980a69a36da7848ab76","tags":["fix","report"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-120831","tags":["web","advisory"]},{"url":"https://github.com/advisories/GHSA-c4qr-qpmh-whrf"},{"url":"https://access.redhat.com/downloads/content/package-browser/","tags":["web"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/120xxx/CVE-2026-120831.json","tags":["advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-120831","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2026-120831","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-120831","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2026-120831","title":"Libslirp: libslirp: queue pointer corruption in if_output() leading to denial of service","description":"A flaw was found in libslirp in if_output(). When moving a session from the fast queue to the batch queue, the code unlinked and reinserted an arbitrary packet via ifm-\u003em_nextpkt instead of the session queue head, corrupting queue pointers. A guest generating burst traffic could crash the host networking process, causing a denial of service.","status":"published","published":"2026-11-03T01:55:20.336Z","modified":"2026-11-05T19:03:11.989Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"cna"}],"cwes":["CWE-787"],"updated_at":"2026-11-05T20:54:59.423743Z"}],"euvd":[{"id":"EUVD-2026-115656","description":"A flaw was found in libslirp in if_output(). When moving a session from the fast queue to the batch queue, the code unlinked and reinserted an arbitrary packet via ifm-\u003em_nextpkt instead of the session queue head, corrupting queue pointers. A guest generating burst traffic could crash the host networking process, causing a denial of service.","status":"published","published":"2026-11-03T01:55:20Z","modified":"2026-11-05T19:03:11Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-05T20:01:48.85376Z"}],"ghsa":[{"id":"GHSA-c4qr-qpmh-whrf","title":"A flaw was found in libslirp in if_output(). When moving a session from the fast queue to the...","description":"A flaw was found in libslirp in if_output(). When moving a session from the fast queue to the batch queue, the code unlinked and reinserted an arbitrary packet via ifm-\u003em_nextpkt instead of the session queue head, corrupting queue pointers. A guest generating burst traffic could crash the host networking process, causing a denial of service.","status":"published","published":"2026-11-03T03:30:22Z","modified":"2026-11-03T03:30:22Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"cwes":["CWE-787"],"updated_at":"2026-11-03T03:49:03.128673Z"}],"nvd":[{"id":"CVE-2026-120831","description":"A flaw was found in libslirp in if_output(). When moving a session from the fast queue to the batch queue, the code unlinked and reinserted an arbitrary packet via ifm-\u003em_nextpkt instead of the session queue head, corrupting queue pointers. A guest generating burst traffic could crash the host networking process, causing a denial of service.","status":"published","published":"2026-11-03T02:16:53.393Z","modified":"2026-11-05T19:17:14.887Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"secondary"}],"cwes":["CWE-787"],"updated_at":"2026-11-05T21:56:48.940931Z"}],"osv":[{"id":"CVE-2026-120831","title":"Libslirp: libslirp: queue pointer corruption in if_output() leading to denial of service","description":"A flaw was found in libslirp in if_output(). When moving a session from the fast queue to the batch queue, the code unlinked and reinserted an arbitrary packet via ifm-\u003em_nextpkt instead of the session queue head, corrupting queue pointers. A guest generating burst traffic could crash the host networking process, causing a denial of service.","status":"published","published":"2026-11-03T01:55:20.336Z","modified":"2026-11-07T07:05:06.725233339Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"cwes":["CWE-787"],"updated_at":"2026-11-07T03:08:01.726202Z"},{"id":"DEBIAN-CVE-2026-120831","description":"A flaw was found in libslirp in if_output(). When moving a session from the fast queue to the batch queue, the code unlinked and reinserted an arbitrary packet via ifm-\u003em_nextpkt instead of the session queue head, corrupting queue pointers. A guest generating burst traffic could crash the host networking process, causing a denial of service.","status":"published","published":"2026-11-03T02:16:53.393Z","modified":"2026-11-04T09:47:27.173791361Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-04T10:05:57.467041Z"},{"id":"UBUNTU-CVE-2026-120831","description":"A flaw was found in libslirp in if_output(). When moving a session from the fast queue to the batch queue, the code unlinked and reinserted an arbitrary packet via ifm-\u003em_nextpkt instead of the session queue head, corrupting queue pointers. A guest generating burst traffic could crash the host networking process, causing a denial of service.","status":"published","published":"2026-11-03T02:16:00Z","modified":"2026-11-05T04:42:52Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-05T13:33:25.727744Z"},{"id":"AZL-112682","title":"CVE-2026-120831 affecting package libslirp 4.9.6-1","description":"A flaw was found in libslirp in if_output(). When moving a session from the fast queue to the batch queue, the code unlinked and reinserted an arbitrary packet via ifm-\u003em_nextpkt instead of the session queue head, corrupting queue pointers. A guest generating burst traffic could crash the host networking process, causing a denial of service.","status":"published","published":"2026-11-03T02:16:53Z","modified":"2026-11-05T14:17:04.861954614Z","updated_at":"2026-11-05T16:41:19.001909Z"}]}}