{"id":"CVE-2026-89645","title":"kernel: btrfs: drop recovered reloc root refs on recovery failure (CVE-2026-89645)","summary":"A flaw was found in the btrfs file system in the Linux kernel. During relocation recovery, if an error occurs, such as a memory allocation failure, the system may not properly drop references to relocation roots. This oversight can lead to…","severity":"medium","cvss":5.5,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","cvssSource":"vendor","cwe":"CWE-911","vendor":"Red Hat","product":"Red Hat Enterprise Linux 10","affected":["enterprise_linux 10","enterprise_linux 6"],"published":"2026-09-11","updated":"2026-09-18","sourceUpdated":"2026-09-18T22:07:40+00:00","source":"CSAF","sourceUrl":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89645.json","references":[{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89645.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-89645"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532260"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89645"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89645"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89645.mbox"},{"url":"https://git.kernel.org/stable/c/2256d6dc5b88841a8a8b4fd9a9f04730705fb6fd"},{"url":"https://git.kernel.org/stable/c/4d43107e807bcd92621106b07f5011411c6341a8"},{"url":"https://git.kernel.org/stable/c/6d8ba4572922e336f0b59a80751b018e1e135164"},{"url":"https://git.kernel.org/stable/c/8a64baeb5bbb706b83d2235c1e39f5b77183817f"}],"tags":["csaf","vex","red-hat","cve.org"],"epss":0.00225,"epssPercentile":0.13349,"ingestedAt":"2026-09-14T11:11:19.885Z","slug":"CVE-2026-89645","body":"## Overview\n\nA flaw was found in the btrfs file system in the Linux kernel. During relocation recovery, if an error occurs, such as a memory allocation failure, the system may not properly drop references to relocation roots. This oversight can lead to resource exhaustion, potentially allowing a local attacker to cause a denial of service (DoS) by making the system unresponsive or unstable.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Low · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 10 · updated 2026-09-18 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89645.json)\n\n**kernel: btrfs: drop recovered reloc root refs on recovery failure** — rated Low by Red Hat. Released 2026-09-11, updated 2026-09-18.\n\nAffected:\n\n- Red Hat Enterprise Linux 10\n- Red Hat Enterprise Linux 6\n\nNo fix planned:\n\n- Red Hat Enterprise Linux 6\n- Red Hat Enterprise Linux 10\n\nNot affected:\n\n- Red Hat Enterprise Linux 7\n- Red Hat Enterprise Linux 8\n- Red Hat Enterprise Linux 9\n- Red Hat OpenShift Container Platform 4\n\n## Remediation\n\nOut of support scope","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":30.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":208089,"id":"CVE-2026-89645","ts":1789922707364,"field":"cvss","old":"4.4","new":"5.5"},{"seq":204041,"id":"CVE-2026-89645","ts":1789490231164,"field":"cvss","old":null,"new":"4.4"},{"seq":204040,"id":"CVE-2026-89645","ts":1789490231164,"field":"severity","old":"none","new":"medium"},{"seq":147476,"id":"CVE-2026-89645","ts":1789270211058,"field":"cvss","old":null,"new":"4.4"},{"seq":147475,"id":"CVE-2026-89645","ts":1789270211058,"field":"severity","old":"none","new":"medium"},{"seq":109232,"id":"CVE-2026-89645","ts":1789183731072,"field":"cvss","old":null,"new":"4.4"},{"seq":109231,"id":"CVE-2026-89645","ts":1789183731072,"field":"severity","old":"none","new":"medium"}]}