{"id":"CVE-2026-89748","title":"tracing: Fix retry exhaustion in simple ring buffer reader swap","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Fix retry exhaustion in simple ring buffer reader swap\n\nsimple_ring_buffer_swap_reader_page() starts with retry set to 8 and\npost-decrements it only after a fa…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","cwe":["CWE-787"],"vendor":"Linux","product":"Linux","affected":["Linux >= 34e5b958bdad0f9cf16306368bbc2dc5b2a50143 < df02489aa3aa1834659f0d20c89f7d212047d268","Linux >= 34e5b958bdad0f9cf16306368bbc2dc5b2a50143 < e0d3aed7b12cf37b74c7cc5265073d0263b49cde","Linux 7.1"],"published":"2026-09-11","updated":"2026-10-19","sourceUpdated":"2026-10-19T08:52:02.172Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-89748","references":[{"url":"https://git.kernel.org/stable/c/df02489aa3aa1834659f0d20c89f7d212047d268"},{"url":"https://git.kernel.org/stable/c/e0d3aed7b12cf37b74c7cc5265073d0263b49cde"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89748.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-89748"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532233"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89748"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89748"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89748.mbox"}],"tags":["cve.org","csaf","vex","red-hat","score-dispute"],"epss":0.00165,"epssPercentile":0.05678,"scores":{"cna":7.8,"vendor":5.5},"ingestedAt":"2026-09-14T15:23:07.472Z","slug":"CVE-2026-89748","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Fix retry exhaustion in simple ring buffer reader swap\n\nsimple_ring_buffer_swap_reader_page() starts with retry set to 8 and\npost-decrements it only after a failed link replacement. On the final\nattempt, a successful replacement leaves retry at zero, while a failed\nreplacement leaves it at -1.\n\nThe current !retry test reverses both outcomes. It returns an error after\na successful final replacement, leaving the link update complete but the\nreader bookkeeping unfinished. After a failed final replacement, it\nfalls through and updates the head and reader pointers as though the\nreplacement succeeded, which can corrupt the ring.\n\nTreat only a negative counter as exhaustion and return the documented\n-EBUSY error.\n\n## Affected\n\n- `Linux >= 34e5b958bdad0f9cf16306368bbc2dc5b2a50143 < df02489aa3aa1834659f0d20c89f7d212047d268`\n- `Linux >= 34e5b958bdad0f9cf16306368bbc2dc5b2a50143 < e0d3aed7b12cf37b74c7cc5265073d0263b49cde`\n- `Linux 7.1`\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** · Moderate · updated 2026-09-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89748.json)","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":224574,"id":"CVE-2026-89748","ts":1792401417038,"field":"cvss","old":"5.5","new":"7.8"},{"seq":224573,"id":"CVE-2026-89748","ts":1792401417038,"field":"severity","old":"medium","new":"high"},{"seq":208947,"id":"CVE-2026-89748","ts":1790062297893,"field":"cvss","old":"6.1","new":"5.5"},{"seq":202966,"id":"CVE-2026-89748","ts":1789403733147,"field":"cvss","old":"7.8","new":"6.1"},{"seq":202965,"id":"CVE-2026-89748","ts":1789403733147,"field":"severity","old":"high","new":"medium"},{"seq":197678,"id":"CVE-2026-89748","ts":1789384318357,"field":"cvss","old":"6.1","new":"7.8"},{"seq":197677,"id":"CVE-2026-89748","ts":1789384318357,"field":"severity","old":"medium","new":"high"},{"seq":183651,"id":"CVE-2026-89748","ts":1789356676263,"field":"cvss","old":"7.8","new":"6.1"},{"seq":183650,"id":"CVE-2026-89748","ts":1789356676263,"field":"severity","old":"high","new":"medium"},{"seq":153636,"id":"CVE-2026-89748","ts":1789285351651,"field":"cvss","old":null,"new":"7.8"},{"seq":153635,"id":"CVE-2026-89748","ts":1789285351651,"field":"severity","old":"none","new":"high"},{"seq":147524,"id":"CVE-2026-89748","ts":1789270211244,"field":"cvss","old":null,"new":"6.1"},{"seq":147523,"id":"CVE-2026-89748","ts":1789270211244,"field":"severity","old":"none","new":"medium"},{"seq":109270,"id":"CVE-2026-89748","ts":1789183731221,"field":"cvss","old":null,"new":"6.1"},{"seq":109269,"id":"CVE-2026-89748","ts":1789183731221,"field":"severity","old":"none","new":"medium"}]}