{"id":"CVE-2026-68155","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nlibceph: Reject monmaps advertising zero monitors\n\nA message of type CEPH_MSG_MON_MAP contains a monmap that is sent from a\nmonitor to the client","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nlibceph: Reject monmaps advertising zero monitors\n\nA message of type CEPH_MSG_MON_MAP contains a monmap that is sent from a\nmonitor to the client. This monmap contains …","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","vendor":"Linux","product":"Linux","affected":["Linux >= ba75bb98cfb93b62c54af25bf67ff90857264bbe < ba5f0015bfd376d764163045a61c17be75f44dae","Linux >= ba75bb98cfb93b62c54af25bf67ff90857264bbe < caf082ef8609a6ac26159ce115f55ab7d00231a3","Linux >= ba75bb98cfb93b62c54af25bf67ff90857264bbe < e3ccd4ecab09b22f507f49cb7ed9990c7158ceab","Linux >= ba75bb98cfb93b62c54af25bf67ff90857264bbe < 0591a15815b498be628a937146e44487d599ba33","Linux >= ba75bb98cfb93b62c54af25bf67ff90857264bbe < cd0d41bc569632eaaeccde9d2a6bc919ec00c407","Linux >= ba75bb98cfb93b62c54af25bf67ff90857264bbe < e67e8b694872c9bc66996040f9de9242f6236ed9","Linux >= ba75bb98cfb93b62c54af25bf67ff90857264bbe < 3b249546f59c3d6d3592c10657f82bc3f1faa07c","Linux >= ba75bb98cfb93b62c54af25bf67ff90857264bbe < 40480eee361ed9676b3f844d532ac28b47251634","Linux 2.6.34"],"published":"2026-08-10","updated":"2026-10-03","sourceUpdated":"2026-10-03T11:17:35.793","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-68155","references":[{"url":"https://git.kernel.org/stable/c/0591a15815b498be628a937146e44487d599ba33","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/3b249546f59c3d6d3592c10657f82bc3f1faa07c","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/40480eee361ed9676b3f844d532ac28b47251634","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ba5f0015bfd376d764163045a61c17be75f44dae","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/caf082ef8609a6ac26159ce115f55ab7d00231a3","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/cd0d41bc569632eaaeccde9d2a6bc919ec00c407","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/e3ccd4ecab09b22f507f49cb7ed9990c7158ceab","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/e67e8b694872c9bc66996040f9de9242f6236ed9","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd","cve.org"],"epss":0.0068,"epssPercentile":0.50667,"ingestedAt":"2026-10-03T11:43:42.115Z","slug":"CVE-2026-68155","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nlibceph: Reject monmaps advertising zero monitors\n\nA message of type CEPH_MSG_MON_MAP contains a monmap that is sent from a\nmonitor to the client. This monmap contains information about the\nexisting monitors in the cluster. Currently, a monmap indicating that\nthere are zero monitors in the cluster is treated as valid. However, it\nis impossible to have zero monitors in the cluster and still receive a\nvalid monmap from a monitor. Therefore, such a monmap must be corrupted\nand should be treated as invalid. Furthermore, a monmap with a monitor\ncount of zero can subsequently crash the client when attempting to open\na session with a monitor in __open_session(). This happens because the\n\"BUG_ON(monc->monmap->num_mon < 1)\" assertion in pick_new_mon() is\ntriggered.\n\nThis patch extends a check in ceph_monmap_decode() to also reject\narriving mon_maps with num_mon == 0 rather than only with\nnum_mon > CEPH_MAX_MON.\n\n[ idryomov: drop \"log output for unusual values of num_mon\" part ]\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}