{"id":"CVE-2026-89526","title":"svcrdma: Validate Read chunk positions before reconstruction","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nsvcrdma: Validate Read chunk positions before reconstruction\n\nThe RPC/RDMA Read chunk position field is supplied by the remote\nclient and stored verbatim in the parsed …","severity":"critical","cvss":9.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","cwe":["CWE-125"],"vendor":"Linux","product":"Linux","affected":["Linux >= d96962e6d0e281bab6a48e83b42f5dce6eb28bf4 < 3861eeabaebe243050952b34063763527c44e1fe","Linux >= d96962e6d0e281bab6a48e83b42f5dce6eb28bf4 < 5ab3f6d882fe07ae5e61d0bcfeea00b9409155c2","Linux >= d96962e6d0e281bab6a48e83b42f5dce6eb28bf4 < f84ec84d8d4bc65f9ae23372570349687f66fa39","Linux >= d96962e6d0e281bab6a48e83b42f5dce6eb28bf4 < 577097455d084610fc31e91e6a61c5793b6f04ba","Linux >= d96962e6d0e281bab6a48e83b42f5dce6eb28bf4 < 3779b7b9e7d1c8ba4738f9d327de3b0288cefe9b","Linux 5.11"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"total","timestamp":"2026-10-16T19:22:57.126783Z"},"published":"2026-09-11","updated":"2026-10-21","sourceUpdated":"2026-10-21T12:47:39.359Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-89526","references":[{"url":"https://git.kernel.org/stable/c/3861eeabaebe243050952b34063763527c44e1fe"},{"url":"https://git.kernel.org/stable/c/5ab3f6d882fe07ae5e61d0bcfeea00b9409155c2"},{"url":"https://git.kernel.org/stable/c/f84ec84d8d4bc65f9ae23372570349687f66fa39"},{"url":"https://git.kernel.org/stable/c/577097455d084610fc31e91e6a61c5793b6f04ba"},{"url":"https://git.kernel.org/stable/c/3779b7b9e7d1c8ba4738f9d327de3b0288cefe9b"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89526.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-89526"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532309"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89526"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89526"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89526.mbox"}],"tags":["cve.org","csaf","vex","red-hat"],"epss":0.00635,"epssPercentile":0.50214,"scores":{"cna":9.8,"vendor":8.1},"ingestedAt":"2026-09-14T15:23:07.475Z","slug":"CVE-2026-89526","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nsvcrdma: Validate Read chunk positions before reconstruction\n\nThe RPC/RDMA Read chunk position field is supplied by the remote\nclient and stored verbatim in the parsed chunk list.\nxdr_count_read_segments() checks only 4-byte alignment; it never\ncompares the position against the received inline body length.\n\nIn the single-chunk path, svc_rdma_read_complete_one() splits the\nhead and tail kvecs at ch_position. A position past the inline\nbody underflows the tail length, exposing adjacent slab memory to\nthe upper XDR decoder.\n\nIn the multi-chunk path, svc_rdma_read_multiple_chunks() computes\ngap lengths between chunks as unsigned subtractions from\nch_position. Overlapping Read chunks cause these subtractions to\nunderflow. A final position past the inline body likewise\nunderflows the trailing gap length. svc_rdma_copy_inline_range()\nthen copies past the receive buffer into request pages that are\nreturned to the client through the Reply channel.\n\nBound inline-range copies in svc_rdma_copy_inline_range() against\nthe decoded inline RPC body saved in rc_saved_arg. Reject a\nsingle Read chunk positioned beyond that body, and reject\nmulti-chunk lists where accumulated read bytes exceed the next\nchunk's position. Apply the same position and overlap checks in\nthe call-chunk interleaving path.\n\n## Affected\n\n- `Linux >= d96962e6d0e281bab6a48e83b42f5dce6eb28bf4 < 3861eeabaebe243050952b34063763527c44e1fe`\n- `Linux >= d96962e6d0e281bab6a48e83b42f5dce6eb28bf4 < 5ab3f6d882fe07ae5e61d0bcfeea00b9409155c2`\n- `Linux >= d96962e6d0e281bab6a48e83b42f5dce6eb28bf4 < f84ec84d8d4bc65f9ae23372570349687f66fa39`\n- `Linux >= d96962e6d0e281bab6a48e83b42f5dce6eb28bf4 < 577097455d084610fc31e91e6a61c5793b6f04ba`\n- `Linux >= d96962e6d0e281bab6a48e83b42f5dce6eb28bf4 < 3779b7b9e7d1c8ba4738f9d327de3b0288cefe9b`\n- `Linux 5.11`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · updated 2026-09-27 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89526.json)","depth":"midnight","depthScore":54,"depthScoreParts":{"impact":53.9,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":223302,"id":"CVE-2026-89526","ts":1792180050365,"field":"cvss","old":"8.1","new":"9.8"},{"seq":223301,"id":"CVE-2026-89526","ts":1792180050365,"field":"severity","old":"high","new":"critical"},{"seq":211829,"id":"CVE-2026-89526","ts":1790581656230,"field":"cvss","old":"7","new":"8.1"},{"seq":205473,"id":"CVE-2026-89526","ts":1789576721434,"field":"cvss","old":"8.1","new":"7"},{"seq":203027,"id":"CVE-2026-89526","ts":1789403733402,"field":"cvss","old":"9.8","new":"8.1"},{"seq":203026,"id":"CVE-2026-89526","ts":1789403733402,"field":"severity","old":"critical","new":"high"},{"seq":197971,"id":"CVE-2026-89526","ts":1789384321202,"field":"cvss","old":"8.1","new":"9.8"},{"seq":197970,"id":"CVE-2026-89526","ts":1789384321202,"field":"severity","old":"high","new":"critical"},{"seq":183772,"id":"CVE-2026-89526","ts":1789356677320,"field":"cvss","old":"9.8","new":"8.1"},{"seq":183771,"id":"CVE-2026-89526","ts":1789356677320,"field":"severity","old":"critical","new":"high"},{"seq":153318,"id":"CVE-2026-89526","ts":1789285350023,"field":"cvss","old":null,"new":"9.8"},{"seq":153317,"id":"CVE-2026-89526","ts":1789285350023,"field":"severity","old":"none","new":"critical"},{"seq":147416,"id":"CVE-2026-89526","ts":1789270210824,"field":"cvss","old":null,"new":"8.1"},{"seq":147415,"id":"CVE-2026-89526","ts":1789270210824,"field":"severity","old":"none","new":"high"},{"seq":109154,"id":"CVE-2026-89526","ts":1789183730524,"field":"cvss","old":null,"new":"8.1"},{"seq":109153,"id":"CVE-2026-89526","ts":1789183730524,"field":"severity","old":"none","new":"high"}]}