{"id":"CVE-2025-21836","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/kbuf: reallocate buf lists on upgrade\n\nIORING_REGISTER_PBUF_RING can reuse an old struct io_buffer_list if it\nwas created for legacy selected buffer and has be…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/kbuf: reallocate buf lists on upgrade\n\nIORING_REGISTER_PBUF_RING can reuse an old struct io_buffer_list if it\nwas created for legacy selected buffer and has be…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","vendor":"linux","product":"linux_kernel","affected":["linux_kernel >= 5.19, < 6.6.79","linux_kernel >= 6.7, < 6.12.16","linux_kernel >= 6.13, < 6.13.4","linux_kernel = 6.14"],"patched":["linux_kernel 6.13.4"],"published":"2025-03-07","updated":"2026-07-30","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2025-21836","references":[{"url":"https://git.kernel.org/stable/c/146a185f6c05ee263db715f860620606303c4633","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/2a5febbef40ce968e295a7aeaa5d5cbd9e3e5ad4","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/7d0dc28dae836caf7645fef62a10befc624dd17b","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/8802766324e1f5d414a81ac43365c20142e85603","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://u1f383.github.io/slides/talks/2025_Hexacon-Deja_Vu_in_Linux_io_uring_Breaking_Memory_Sharing_Again_After_Generations_of_Fixes.pdf","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd"],"epss":0.00247,"epssPercentile":0.1629,"ingestedAt":"2026-07-30T06:53:10.406Z","slug":"CVE-2025-21836","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/kbuf: reallocate buf lists on upgrade\n\nIORING_REGISTER_PBUF_RING can reuse an old struct io_buffer_list if it\nwas created for legacy selected buffer and has been emptied. It violates\nthe requirement that most of the field should stay stable after publish.\nAlways reallocate it instead.\n\n## Affected\n\n- `linux_kernel >= 5.19, < 6.6.79`\n- `linux_kernel >= 6.7, < 6.12.16`\n- `linux_kernel >= 6.13, < 6.13.4`\n- `linux_kernel = 6.14`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `linux_kernel 6.13.4`","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}