{"affected":[{"defaultStatus":"unaffected","product":"Linux","source":"CNA: Linux","vendor":"Linux","versions":[{"lessThan":"64a99eff8dcf1f951a544e6058341b2b19a8fdbd","status":"affected","version":"6a6dcae8f486c3f3298d0767d34505121c7b0b81","versionType":"git"},{"lessThan":"29d39e0d5f16c060e32542b2cf351c09fd22b250","status":"affected","version":"6a6dcae8f486c3f3298d0767d34505121c7b0b81","versionType":"git"},{"lessThan":"911ef2e8a7de5b2bae8ff11fb0bd01f699e6db65","status":"affected","version":"6a6dcae8f486c3f3298d0767d34505121c7b0b81","versionType":"git"},{"lessThan":"df831e97739405ecbaddb85516bc7d4d1c933d6b","status":"affected","version":"6a6dcae8f486c3f3298d0767d34505121c7b0b81","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","source":"CNA: Linux","vendor":"Linux","versions":[{"status":"affected","version":"6.3"},{"lessThan":"6.3","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.96","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.36","versionType":"semver"},{"lessThanOrEqual":"6.15.*","status":"unaffected","version":"6.15.5","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"6.16","versionType":"original_commit_for_fix"}]}],"cveId":"CVE-2025-38255","cwes":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nlib/group_cpus: fix NULL pointer dereference from group_cpus_evenly()\n\nWhile testing null_blk with configfs, echo 0 > poll_queues will trigger\nfollowing panic:\n\nBUG: kernel NULL pointer dereference, address: 0000000000000010\nOops: Oops: 0000 [#1] SMP NOPTI\nCPU: 27 UID: 0 PID: 920 Comm: bash Not tainted 6.15.0-02023-gadbdb95c8696-dirty #1238 PREEMPT(undef)\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.1-2.fc37 04/01/2014\nRIP: 0010:__bitmap_or+0x48/0x70\nCall Trace:\n <TASK>\n __group_cpus_evenly+0x822/0x8c0\n group_cpus_evenly+0x2d9/0x490\n blk_mq_map_queues+0x1e/0x110\n null_map_queues+0xc9/0x170 [null_blk]\n blk_mq_update_queue_map+0xdb/0x160\n blk_mq_update_nr_hw_queues+0x22b/0x560\n nullb_update_nr_hw_queues+0x71/0xf0 [null_blk]\n nullb_device_poll_queues_store+0xa4/0x130 [null_blk]\n configfs_write_iter+0x109/0x1d0\n vfs_write+0x26e/0x6f0\n ksys_write+0x79/0x180\n __x64_sys_write+0x1d/0x30\n x64_sys_call+0x45c4/0x45f0\n do_syscall_64+0xa5/0x240\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nRoot cause is that numgrps is set to 0, and ZERO_SIZE_PTR is returned from\nkcalloc(), and later ZERO_SIZE_PTR will be deferenced.\n\nFix the problem by checking numgrps first in group_cpus_evenly(), and\nreturn NULL directly if numgrps is zero.\n\n[yukuai3@huawei.com: also fix the non-SMP version]","epss":{"date":"2026-11-05","percentile":0.05846,"score":0.00166},"exploits":[],"kev":null,"metrics":[],"modifiedAt":1793912549328,"publishedAt":1752057753225,"references":[{"source":"CNA: Linux","tags":[],"url":"https://git.kernel.org/stable/c/64a99eff8dcf1f951a544e6058341b2b19a8fdbd"},{"source":"CNA: Linux","tags":[],"url":"https://git.kernel.org/stable/c/29d39e0d5f16c060e32542b2cf351c09fd22b250"},{"source":"CNA: Linux","tags":[],"url":"https://git.kernel.org/stable/c/911ef2e8a7de5b2bae8ff11fb0bd01f699e6db65"},{"source":"CNA: Linux","tags":[],"url":"https://git.kernel.org/stable/c/df831e97739405ecbaddb85516bc7d4d1c933d6b"}],"remediation":[],"revision":"e424377d7a8d5c8da4efed2c56624dadb3c9cfe1d2bf0abad79d432b0a36dc9e","sources":[{"modifiedAt":1793912549328,"name":"CNA: Linux","retrievedAt":1793913628338,"url":"https://www.cve.org/CVERecord?id=CVE-2025-38255"},{"modifiedAt":null,"name":"FIRST EPSS","retrievedAt":1793913633768,"url":"https://api.first.org/data/v1/epss?cve=CVE-2025-38255"}],"ssvc":{"assessedAt":1793911945572,"automatable":"no","exploitation":"none","source":"ADP: CISA-ADP","technicalImpact":"partial"},"status":"published","title":"lib/group_cpus: fix NULL pointer dereference from group_cpus_evenly()","updatedAt":1793913633768}