{"cve":"CVE-2025-38263","nvd":{"published":"2025-07-09T11:15:28.690","modified":"2026-06-17T09:16:30.480","status":"Analyzed","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbcache: fix NULL pointer in cache_set_flush()\n\n1. LINE#1794 - LINE#1887 is some codes about function of\n   bch_cache_set_alloc().\n2. LINE#2078 - LINE#2142 is some codes about function of\n   register_cache_set().\n3. register_cache_set() will call bch_cache_set_alloc() in LINE#2098.\n\n 1794 struct cache_set *bch_cache_set_alloc(struct cache_sb *sb)\n 1795 {\n ...\n 1860         if (!(c->devices = kcalloc(c->nr_uuids, sizeof(void *), GFP_KERNEL)) ||\n 1861             mempool_init_slab_pool(&c->search, 32, bch_search_cache) ||\n 1862             mempool_init_kmalloc_pool(&c->bio_meta, 2,\n 1863                                 sizeof(struct bbio) + sizeof(struct bio_vec) *\n 1864                                 bucket_pages(c)) ||\n 1865             mempool_init_kmalloc_pool(&c->fill_iter, 1, iter_size) ||\n 1866             bioset_init(&c->bio_split, 4, offsetof(struct bbio, bio),\n 1867                         BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER) ||\n 1868             !(c->uuids = alloc_bucket_pages(GFP_KERNEL, c)) ||\n 1869             !(c->moving_gc_wq = alloc_workqueue(\"bcache_gc\",\n 1870                                                 WQ_MEM_RECLAIM, 0)) ||\n 1871             bch_journal_alloc(c) ||\n 1872             bch_btree_cache_alloc(c) ||\n 1873             bch_open_buckets_alloc(c) ||\n 1874             bch_bset_sort_state_init(&c->sort, ilog2(c->btree_pages)))\n 1875                 goto err;\n                      ^^^^^^^^\n 1876\n ...\n 1883         return c;\n 1884 err:\n 1885         bch_cache_set_unregister(c);\n              ^^^^^^^^^^^^^^^^^^^^^^^^^^^\n 1886         return NULL;\n 1887 }\n ...\n 2078 static const char *register_cache_set(struct cache *ca)\n 2079 {\n ...\n 2098         c = bch_cache_set_alloc(&ca->sb);\n 2099         if (!c)\n 2100                 return err;\n                      ^^^^^^^^^^\n ...\n 2128         ca->set = c;\n 2129         ca->set->cache[ca->sb.nr_this_dev] = ca;\n              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n ...\n 2138         return NULL;\n 2139 err:\n 2140         bch_cache_set_unregister(c);\n 2141         return err;\n 2142 }\n\n(1) If LINE#1860 - LINE#1874 is true, then do 'goto err'(LINE#1875) and\n    call bch_cache_set_unregister()(LINE#1885).\n(2) As (1) return NULL(LINE#1886), LINE#2098 - LINE#2100 would return.\n(3) As (2) has returned, LINE#2128 - LINE#2129 would do *not* give the\n    value to c->cache[], it means that c->cache[] is NULL.\n\nLINE#1624 - LINE#1665 is some codes about function of cache_set_flush().\nAs (1), in LINE#1885 call\nbch_cache_set_unregister()\n---> bch_cache_set_stop()\n     ---> closure_queue()\n          -.-> cache_set_flush() (as below LINE#1624)\n\n 1624 static void cache_set_flush(struct closure *cl)\n 1625 {\n ...\n 1654         for_each_cache(ca, c, i)\n 1655                 if (ca->alloc_thread)\n                          ^^\n 1656                         kthread_stop(ca->alloc_thread);\n ...\n 1665 }\n\n(4) In LINE#1655 ca is NULL(see (3)) in cache_set_flush() then the\n    kernel crash occurred as below:\n[  846.712887] bcache: register_cache() error drbd6: cannot allocate memory\n[  846.713242] bcache: register_bcache() error : failed to register device\n[  846.713336] bcache: cache_set_free() Cache set 2f84bdc1-498a-4f2f-98a7-01946bf54287 unregistered\n[  846.713768] BUG: unable to handle kernel NULL pointer dereference at 00000000000009f8\n[  846.714790] PGD 0 P4D 0\n[  846.715129] Oops: 0000 [#1] SMP PTI\n[  846.715472] CPU: 19 PID: 5057 Comm: kworker/19:16 Kdump: loaded Tainted: G           OE    --------- -  - 4.18.0-147.5.1.el8_1.5es.3.x86_64 #1\n[  846.716082] Hardware name: ESPAN GI-25212/X11DPL-i, BIOS 2.1 06/15/2018\n[  846.716451] Workqueue: events cache_set_flush [bcache]\n[  846.716808] RIP: 0010:cache_set_flush+0xc9/0x1b0 [bcache]\n[  846.717155] Code: 00 4c 89 a5 b0 03 00 00 48 8b 85 68 f6 ff ff a8 08 0f 84 88 00 00 00 31 db 66 83 bd 3c f7 ff ff 00 48 8b 85 48 ff ff ff 74 28 <48> 8b b8 f8 09 00 0\n---truncated---","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":["CWE-476"],"references":["https://git.kernel.org/stable/c/1e46ed947ec658f89f1a910d880cd05e42d3763e","https://git.kernel.org/stable/c/1f25f2d3fa29325320c19a30abf787e0bd5fc91b","https://git.kernel.org/stable/c/3f9e128186c99a117e304f1dce6d0b9e50c63cd8","https://git.kernel.org/stable/c/553f560e0a74a7008ad9dba05c3fd05da296befb","https://git.kernel.org/stable/c/667c3f52373ff5354cb3543e27237eb7df7b2333"],"products":["debian:debian_linux","linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:04:28.436527499+00:00"},"epss":{"cve":"CVE-2025-38263","score":0.00179,"percentile":0.0752,"date":"2026-10-31"},"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."]}