{"id":"CVE-2026-64380","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: harden POSIX SID length parsing\n\nposix_info_sid_size() reads sid[1] to obtain the subauthority count,\nbut its existing boundary check still accepts buffers…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: harden POSIX SID length parsing\n\nposix_info_sid_size() reads sid[1] to obtain the subauthority count,\nbut its existing boundary check still accepts buffers…","severity":"high","cvss":8.2,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H","vendor":"linux","product":"linux_kernel","affected":["linux_kernel >= 5.7, < 5.10.261","linux_kernel >= 5.11, < 5.15.212","linux_kernel >= 5.16, < 6.1.178","linux_kernel >= 6.2, < 6.6.145","linux_kernel >= 6.7, < 6.12.96","linux_kernel >= 6.13, < 6.18.39","linux_kernel >= 6.19, < 7.1.4","linux_kernel = 7.2"],"patched":["linux_kernel 7.1.4"],"published":"2026-07-25","updated":"2026-09-08","sourceUpdated":"2026-09-08T14:06:05.950","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-64380","references":[{"url":"https://git.kernel.org/stable/c/0de5b8e76847f5de26f364a82c6602c4881c30da","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/171605aed68380c2fa75dff9b3a1ed427c50065b","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/4213c1208978483021d7d125c131de3985d38f61","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/427eb7eb46425fec845a43e861f3d6e2899cae59","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/46a84715a015cb48e1b9c219dc88c03d8a541ea4","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/7ad2bcf2441430bb2e918fb3ef9a90d775a6e422","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/86c5d470f5d42e61123b2f4b4f0b91f4eee5b980","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/96e889bc1e759c83f25093e8c2f3da31b4973f30","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd"],"epss":0.00443,"epssPercentile":0.35804,"ingestedAt":"2026-07-27T06:16:50.963Z","slug":"CVE-2026-64380","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: harden POSIX SID length parsing\n\nposix_info_sid_size() reads sid[1] to obtain the subauthority count,\nbut its existing boundary check still accepts buffers with only one\nremaining byte. Require two bytes before reading sid[1] so all client\npaths that reuse the helper reject truncated POSIX SIDs safely.\n\n## Affected\n\n- `linux_kernel >= 5.7, < 5.10.261`\n- `linux_kernel >= 5.11, < 5.15.212`\n- `linux_kernel >= 5.16, < 6.1.178`\n- `linux_kernel >= 6.2, < 6.6.145`\n- `linux_kernel >= 6.7, < 6.12.96`\n- `linux_kernel >= 6.13, < 6.18.39`\n- `linux_kernel >= 6.19, < 7.1.4`\n- `linux_kernel = 7.2`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `linux_kernel 7.1.4`","depth":"twilight","depthScore":45,"depthScoreParts":{"impact":45.1,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}