{"cve":"CVE-2026-89723","nvd":{"published":"2026-09-11T20:20:01.710","modified":"2026-10-19T09:18:12.910","status":"Received","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnilfs2: fix slab-out-of-bounds in nilfs_direct_propagate after truncation\n\nShuangpeng Bai reported that KASAN detected a slab-out-of-bounds error\nin nilfs_direct_propagate() during testing.\n\nAnalysis revealed that after truncating a file, a node block immediately\nbelow the B-tree root was not deleted.  Instead, it remained in the B-tree\nnode cache in a dirty state.  The log writer subsequently detected this\nblock and incorrectly invoked nilfs_direct_propagate() on it, which is\ndesigned to handle only data blocks in direct mapping.\n\nB-tree nodes in the cache are managed by virtual block numbers, and their\nlogical keys typically exceed the range expected by direct mapping.\nConsequently, processing such a node as a direct mapping entry triggers\na slab-out-of-bounds access.\n\nThe root cause is that when a B-tree mapping collapses into a direct\nmapping during truncation, an intermediate node block pointed to by the\nroot node is left behind as garbage instead of being explicitly deleted.\n\nThis resolves the issue by adding a nilfs_btree_discard() operation\nto delete the remaining intermediate node block during the conversion.\nA 'deform' flag is added to the bop_delete interface to explicitly signal\nthat the deletion is part of a mapping transformation.  This allows the\nB-tree mapping implementation to perform the necessary cleanup and\ndiscarding of the residual node structure that would be otherwise be left\norphaned after the transition.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8},"cwes":[],"references":["https://git.kernel.org/stable/c/28362e8ce51377afdec1782e661e808328a10514","https://git.kernel.org/stable/c/39005fd1ce654ffdecacddc406b9a038efe606e6","https://git.kernel.org/stable/c/448636c745a3f3b8582a0b8ce718c890a11c0fa9","https://git.kernel.org/stable/c/45662dedb8f272ef7f16e69f13424c4bd0399240","https://git.kernel.org/stable/c/4a1bb1f9f24a935c9b3f4fbf98012fa6d4ad826d"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:53:43.293028046+00:00"},"epss":{"cve":"CVE-2026-89723","score":0.00169,"percentile":0.06186,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}