{"id":"CVE-2026-89718","summary":"zram: fix out-of-bounds access in writeback_store()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nzram: fix out-of-bounds access in writeback_store()\n\nPatch series \"zram: fix stale scan bounds after reinitialization\".\n\nBoth writeback_store() and read_block_state() derive their table scan\nbounds from zram-\u003edisksize before acquiring dev_lock.  If the device is\nreset and reinitialized with a smaller disksize between that read and lock\nacquisition, the bound can describe the old table while the scan operates\non the new one.  This can lead to out-of-bounds slot accesses.\n\nMove both bound calculations under dev_lock so each bound remains\nconsistent with the table throughout its scan.  Keep the fixes separate\nbecause the affected interfaces originate from different commits and can\nbe backported independently.\n\n\nThis patch (of 2):\n\nwriteback_store() calculates the table scan bounds before taking dev_lock.\nA reset followed by reconfiguration with a smaller disksize can therefore\nreplace zram-\u003etable while writeback_store() is waiting for the lock.  Once\nit acquires the lock, it sees an initialized device but scans the new\ntable using the old upper bound, resulting in an out-of-bounds access.\n\nCalculate the number of pages while holding dev_lock so the scan bound\nmatches the table protected by the lock.","modified":"2026-09-13T03:47:20.414602214Z","published":"2026-09-11T19:46:31.443Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89718.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/07a82a66f8c1894d92e51d97542c32ebf2c51b09"},{"type":"WEB","url":"https://git.kernel.org/stable/c/894913e2d35c46ff19a77530907771ae57862b96"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89718.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89718"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"a939888ec38bf1f33e4a903056677e92a4844244"},{"fixed":"07a82a66f8c1894d92e51d97542c32ebf2c51b09"},{"fixed":"894913e2d35c46ff19a77530907771ae57862b96"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89718.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.0.0"},{"fixed":"7.2.4"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89718.json"}}],"schema_version":"1.9.0"}