{"id":"CVE-2026-52955","state":"PUBLISHED","title":"libceph: Fix potential out-of-bounds access in crush_decode()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nlibceph: Fix potential out-of-bounds access in crush_decode()\n\nA message of type CEPH_MSG_OSD_MAP containing a crush map with at least\none bucket has two fields holding the bucket algorithm. If the values\nin these two fields differ, an out-of-bounds access can occur. This is\nthe case because the first algorithm field (alg) is used to allocate\nthe correct amount of memory for a bucket of this type, while the second\nalgorithm field inside the bucket (b->alg) is used in the subsequent\nprocessing.\n\nThis patch fixes the issue by adding a check that compares alg and\nb->alg and aborts the processing in case they differ. Furthermore,\nb->alg is set to 0 in this case, because the destruction of the crush\nmap also uses this field to determine the bucket type, which can again\nresult in an out-of-bounds access when trying to free the memory pointed\nto by the fields of the bucket. To correctly free the memory allocated\nfor the bucket in such a case, the corresponding call to kfree is moved\nfrom the algorithm-specific crush_destroy_bucket functions to the\ngeneric crush_destroy_bucket().","publishedAt":"2026-06-24T16:28:37.748Z","updatedAt":"2026-10-19T19:47:09.949Z","severity":{"score":9.8,"label":"Critical","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"f24e9980eb860d8600cbe5ef3d2fd9295320d229","status":"affected","lessThan":"6e70ef53e818c53eab28d7b0026b7fd03dddaba5","versionType":"git"},{"version":"f24e9980eb860d8600cbe5ef3d2fd9295320d229","status":"affected","lessThan":"ebe76d58a48a48031b98543d86c4cd30a825b622","versionType":"git"},{"version":"f24e9980eb860d8600cbe5ef3d2fd9295320d229","status":"affected","lessThan":"3f42508191e129ee6b5ea96578d5cab14f2a013a","versionType":"git"},{"version":"f24e9980eb860d8600cbe5ef3d2fd9295320d229","status":"affected","lessThan":"ea0d42137f0c06da71e37ffc647aab4c5309599a","versionType":"git"},{"version":"f24e9980eb860d8600cbe5ef3d2fd9295320d229","status":"affected","lessThan":"cceb10023e76bc89f3fe9238ebd0ccab0fc7c7c5","versionType":"git"},{"version":"f24e9980eb860d8600cbe5ef3d2fd9295320d229","status":"affected","lessThan":"0f3604cbe4df14c5e58288ac9f57511e726a222d","versionType":"git"},{"version":"f24e9980eb860d8600cbe5ef3d2fd9295320d229","status":"affected","lessThan":"fb176a99e4c1a5a8448a83d83d3606203ba81faa","versionType":"git"},{"version":"f24e9980eb860d8600cbe5ef3d2fd9295320d229","status":"affected","lessThan":"4c79fc2d598694bda845b46229c9d48b65042970","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ceph/crush/crush.c","net/ceph/osdmap.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.34","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.34","versionType":"semver"},{"version":"5.10.258","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.209","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.175","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.141","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.91","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.33","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.10","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ceph/crush/crush.c","net/ceph/osdmap.c"]}],"references":["https://git.kernel.org/stable/c/6e70ef53e818c53eab28d7b0026b7fd03dddaba5","https://git.kernel.org/stable/c/ebe76d58a48a48031b98543d86c4cd30a825b622","https://git.kernel.org/stable/c/3f42508191e129ee6b5ea96578d5cab14f2a013a","https://git.kernel.org/stable/c/ea0d42137f0c06da71e37ffc647aab4c5309599a","https://git.kernel.org/stable/c/cceb10023e76bc89f3fe9238ebd0ccab0fc7c7c5","https://git.kernel.org/stable/c/0f3604cbe4df14c5e58288ac9f57511e726a222d","https://git.kernel.org/stable/c/fb176a99e4c1a5a8448a83d83d3606203ba81faa","https://git.kernel.org/stable/c/4c79fc2d598694bda845b46229c9d48b65042970","https://access.redhat.com/security/cve/CVE-2026-52955","https://bugzilla.redhat.com/show_bug.cgi?id=2492328","https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-52955.json"],"weaknesses":["CWE-131"],"ingestedAt":"2026-10-29T20:12:16.098Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/52xxx/CVE-2026-52955.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-52955","state":"PUBLISHED","datePublished":"2026-06-24T16:28:37.748Z","dateUpdated":"2026-10-19T19:47:09.949Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-06-09T07:44:35.373Z"},"containers":{"cna":{"title":"libceph: Fix potential out-of-bounds access in crush_decode()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nlibceph: Fix potential out-of-bounds access in crush_decode()\n\nA message of type CEPH_MSG_OSD_MAP containing a crush map with at least\none bucket has two fields holding the bucket algorithm. If the values\nin these two fields differ, an out-of-bounds access can occur. This is\nthe case because the first algorithm field (alg) is used to allocate\nthe correct amount of memory for a bucket of this type, while the second\nalgorithm field inside the bucket (b->alg) is used in the subsequent\nprocessing.\n\nThis patch fixes the issue by adding a check that compares alg and\nb->alg and aborts the processing in case they differ. Furthermore,\nb->alg is set to 0 in this case, because the destruction of the crush\nmap also uses this field to determine the bucket type, which can again\nresult in an out-of-bounds access when trying to free the memory pointed\nto by the fields of the bucket. To correctly free the memory allocated\nfor the bucket in such a case, the corresponding call to kfree is moved\nfrom the algorithm-specific crush_destroy_bucket functions to the\ngeneric crush_destroy_bucket()."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"f24e9980eb860d8600cbe5ef3d2fd9295320d229","status":"affected","lessThan":"6e70ef53e818c53eab28d7b0026b7fd03dddaba5","versionType":"git"},{"version":"f24e9980eb860d8600cbe5ef3d2fd9295320d229","status":"affected","lessThan":"ebe76d58a48a48031b98543d86c4cd30a825b622","versionType":"git"},{"version":"f24e9980eb860d8600cbe5ef3d2fd9295320d229","status":"affected","lessThan":"3f42508191e129ee6b5ea96578d5cab14f2a013a","versionType":"git"},{"version":"f24e9980eb860d8600cbe5ef3d2fd9295320d229","status":"affected","lessThan":"ea0d42137f0c06da71e37ffc647aab4c5309599a","versionType":"git"},{"version":"f24e9980eb860d8600cbe5ef3d2fd9295320d229","status":"affected","lessThan":"cceb10023e76bc89f3fe9238ebd0ccab0fc7c7c5","versionType":"git"},{"version":"f24e9980eb860d8600cbe5ef3d2fd9295320d229","status":"affected","lessThan":"0f3604cbe4df14c5e58288ac9f57511e726a222d","versionType":"git"},{"version":"f24e9980eb860d8600cbe5ef3d2fd9295320d229","status":"affected","lessThan":"fb176a99e4c1a5a8448a83d83d3606203ba81faa","versionType":"git"},{"version":"f24e9980eb860d8600cbe5ef3d2fd9295320d229","status":"affected","lessThan":"4c79fc2d598694bda845b46229c9d48b65042970","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ceph/crush/crush.c","net/ceph/osdmap.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.34","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.34","versionType":"semver"},{"version":"5.10.258","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.209","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.175","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.141","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.91","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.33","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.10","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ceph/crush/crush.c","net/ceph/osdmap.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/6e70ef53e818c53eab28d7b0026b7fd03dddaba5"},{"url":"https://git.kernel.org/stable/c/ebe76d58a48a48031b98543d86c4cd30a825b622"},{"url":"https://git.kernel.org/stable/c/3f42508191e129ee6b5ea96578d5cab14f2a013a"},{"url":"https://git.kernel.org/stable/c/ea0d42137f0c06da71e37ffc647aab4c5309599a"},{"url":"https://git.kernel.org/stable/c/cceb10023e76bc89f3fe9238ebd0ccab0fc7c7c5"},{"url":"https://git.kernel.org/stable/c/0f3604cbe4df14c5e58288ac9f57511e726a222d"},{"url":"https://git.kernel.org/stable/c/fb176a99e4c1a5a8448a83d83d3606203ba81faa"},{"url":"https://git.kernel.org/stable/c/4c79fc2d598694bda845b46229c9d48b65042970"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":9.8,"baseSeverity":"CRITICAL"},"scenarios":[{"lang":"en","value":"AV:N - The vulnerable CRUSH map is parsed from CEPH_MSG_OSD_MAP messages delivered over Ceph messenger network sessions from monitor or OSD peers.\nAC:L - An attacker controlling a malicious or compromised Ceph peer can choose the two bucket algorithm fields and map contents directly; no race or external timing condition is required.\nPR:N - The attacker needs no privileges on the vulnerable kernel client; the higher-severity reasonable scenario is a malicious or compromised remote Ceph monitor/OSD sending the map.\nUI:N - Once the Ceph client is mounted or an RBD client is connected, OSD map updates are processed automatically without per-attack user action.\nS:U - The corruption occurs in the client kernel and impacts that same kernel security authority, with no VM, IOMMU, or other scope boundary crossed.\nC:H - The mismatch can make the parser/destructor interpret a smaller allocation as a larger bucket type, causing kernel heap out-of-bounds pointer accesses; such memory corruption is reasonably exploitable for information disclosure.\nI:H - The bug can write pointer fields beyond the allocated bucket object and later free through the wrong layout, creating kernel heap corruption with potential control-flow or data integrity compromise.\nA:H - Malformed OSD maps can corrupt kernel memory or trigger invalid frees/oopses, making a kernel crash or denial of service a high-probability impact."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T12:32:05.254Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.34","versionEndExcluding":"5.10.258"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.34","versionEndExcluding":"5.15.209"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.34","versionEndExcluding":"6.1.175"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.34","versionEndExcluding":"6.6.141"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.34","versionEndExcluding":"6.12.91"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.34","versionEndExcluding":"6.18.33"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.34","versionEndExcluding":"7.0.10"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.34","versionEndExcluding":"7.1"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"kernel: libceph: Fix potential out-of-bounds access in crush_decode()","descriptions":[{"lang":"en","value":"A flaw was found in the `libceph` component of the Linux kernel. A remote attacker could send a specially crafted `CEPH_MSG_OSD_MAP` message where two internal fields, `alg` and `b->alg`, contain differing bucket algorithm values. This discrepancy can lead to an out-of-bounds memory access during processing or memory deallocation, potentially causing a system crash and resulting in a Denial of Service (DoS)."}],"affected":[{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 10","packageName":"kernel","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:10"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 6","packageName":"kernel","defaultStatus":"unaffected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:6"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 7","packageName":"kernel","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:7"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 7","packageName":"kernel-rt","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:7"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 8","packageName":"kernel","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:8"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 8","packageName":"kernel-rt","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:8"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 9","packageName":"kernel","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:9"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 9","packageName":"kernel-rt","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:9"]}],"references":[{"url":"https://access.redhat.com/security/cve/CVE-2026-52955","tags":["vdb-entry","x_refsource_REDHAT"]},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2492328","name":"RHBZ#2492328","tags":["issue-tracking","x_refsource_REDHAT"]},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-52955.json","tags":["x_sadp-csaf-vex"]}],"metrics":[{"other":{"content":{"namespace":"https://access.redhat.com/security/updates/classification/","value":"Moderate"},"type":"Red Hat severity rating"}},{"cvssV3_1":{"attackComplexity":"HIGH","attackVector":"LOCAL","availabilityImpact":"HIGH","baseScore":4.7,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"LOW","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"format":"CVSS"}],"problemTypes":[{"descriptions":[{"cweId":"CWE-131","description":"Incorrect Calculation of Buffer Size","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"redhat-SADP","orgId":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c","dateUpdated":"2026-07-15T00:45:47.779Z"},"datePublic":"2026-06-24T00:00:00.000Z","timeline":[{"lang":"en","time":"2026-06-24T00:00:00.000Z","value":"Reported to Red Hat."},{"lang":"en","time":"2026-06-24T00:00:00.000Z","value":"Made public."}],"x_adpType":"supplier","x_generator":{"engine":"sadp-cli 1.0.0"}},{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-52955","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T15:23:26.547216Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-131","lang":"en","type":"CWE","description":"CWE-131 Incorrect Calculation of Buffer Size"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-19T19:47:09.949Z"}}]}}}