{"id":"CVE-2026-43405","title":"libceph: Use u32 for non-negative values in ceph_monmap_decode()","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nlibceph: Use u32 for non-negative values in ceph_monmap_decode()\n\nThis patch fixes unnecessary implicit conversions that change signedness\nof blob_len and num_mon in ce…","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","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= a5cbd5fc22d5043a8a76e15d75d031fe24d1f69c < ee5588e2bc41acb73f6676c0520420c107cd0140","Linux >= a5cbd5fc22d5043a8a76e15d75d031fe24d1f69c < 86f7060cd638d6eb042e8ed780fb83a59ca0dcb3","Linux >= a5cbd5fc22d5043a8a76e15d75d031fe24d1f69c < 5f2806684b05bd24d05c091083b8e2517ba8ffac","Linux >= a5cbd5fc22d5043a8a76e15d75d031fe24d1f69c < b268984ae88cb0dcd7a8e8263962c748448e26e8","Linux >= a5cbd5fc22d5043a8a76e15d75d031fe24d1f69c < ba0a4df8c563536857dcbf7b4dbd0f2a15f57ace","Linux >= a5cbd5fc22d5043a8a76e15d75d031fe24d1f69c < 08bc6173fd611ad5a40f472bf5f15b92aea0fe40","Linux >= a5cbd5fc22d5043a8a76e15d75d031fe24d1f69c < 770444611f047dbfd4517ec0bc1b179d40c2f346","Linux 5.11"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"partial","timestamp":"2026-10-16T15:17:06.278684Z"},"published":"2026-05-08","updated":"2026-10-16","sourceUpdated":"2026-10-16T15:20:40.951Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-43405","references":[{"url":"https://git.kernel.org/stable/c/ee5588e2bc41acb73f6676c0520420c107cd0140"},{"url":"https://git.kernel.org/stable/c/86f7060cd638d6eb042e8ed780fb83a59ca0dcb3"},{"url":"https://git.kernel.org/stable/c/5f2806684b05bd24d05c091083b8e2517ba8ffac"},{"url":"https://git.kernel.org/stable/c/b268984ae88cb0dcd7a8e8263962c748448e26e8"},{"url":"https://git.kernel.org/stable/c/ba0a4df8c563536857dcbf7b4dbd0f2a15f57ace"},{"url":"https://git.kernel.org/stable/c/08bc6173fd611ad5a40f472bf5f15b92aea0fe40"},{"url":"https://git.kernel.org/stable/c/770444611f047dbfd4517ec0bc1b179d40c2f346"}],"tags":["cve.org"],"epss":0.007,"epssPercentile":0.52217,"ingestedAt":"2026-10-16T17:24:46.694Z","slug":"CVE-2026-43405","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nlibceph: Use u32 for non-negative values in ceph_monmap_decode()\n\nThis patch fixes unnecessary implicit conversions that change signedness\nof blob_len and num_mon in ceph_monmap_decode().\nCurrently blob_len and num_mon are (signed) int variables. They are used\nto hold values that are always non-negative and get assigned in\nceph_decode_32_safe(), which is meant to assign u32 values. Both\nvariables are subsequently used as unsigned values, and the value of\nnum_mon is further assigned to monmap->num_mon, which is of type u32.\nTherefore, both variables should be of type u32. This is especially\nrelevant for num_mon. If the value read from the incoming message is\nvery large, it is interpreted as a negative value, and the check for\nnum_mon > CEPH_MAX_MON does not catch it. This leads to the attempt to\nallocate a very large chunk of memory for monmap, which will most likely\nfail. In this case, an unnecessary attempt to allocate memory is\nperformed, and -ENOMEM is returned instead of -EINVAL.\n\n## Affected\n\n- `Linux >= a5cbd5fc22d5043a8a76e15d75d031fe24d1f69c < ee5588e2bc41acb73f6676c0520420c107cd0140`\n- `Linux >= a5cbd5fc22d5043a8a76e15d75d031fe24d1f69c < 86f7060cd638d6eb042e8ed780fb83a59ca0dcb3`\n- `Linux >= a5cbd5fc22d5043a8a76e15d75d031fe24d1f69c < 5f2806684b05bd24d05c091083b8e2517ba8ffac`\n- `Linux >= a5cbd5fc22d5043a8a76e15d75d031fe24d1f69c < b268984ae88cb0dcd7a8e8263962c748448e26e8`\n- `Linux >= a5cbd5fc22d5043a8a76e15d75d031fe24d1f69c < ba0a4df8c563536857dcbf7b4dbd0f2a15f57ace`\n- `Linux >= a5cbd5fc22d5043a8a76e15d75d031fe24d1f69c < 08bc6173fd611ad5a40f472bf5f15b92aea0fe40`\n- `Linux >= a5cbd5fc22d5043a8a76e15d75d031fe24d1f69c < 770444611f047dbfd4517ec0bc1b179d40c2f346`\n- `Linux 5.11`\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":[]}