{"id":"CVE-2025-21640","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nsctp: sysctl: cookie_hmac_alg: avoid using current->nsproxy\n\nAs mentioned in a previous commit of this series, using the 'net'\nstructure via 'current' is not recommende…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nsctp: sysctl: cookie_hmac_alg: avoid using current->nsproxy\n\nAs mentioned in a previous commit of this series, using the 'net'\nstructure via 'current' is not recommende…","severity":"high","cvss":7.1,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H","cwe":["CWE-476"],"vendor":"linux","product":"linux_kernel","affected":["linux_kernel >= 3.8, < 6.1.125","linux_kernel >= 6.2, < 6.6.72","linux_kernel >= 6.7, < 6.12.10","linux_kernel = 6.13"],"patched":["linux_kernel 6.12.10"],"published":"2025-01-19","updated":"2026-07-30","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2025-21640","references":[{"url":"https://git.kernel.org/stable/c/03ca51faba2b017bf6c90e139434c4117d0afcdc","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/3cd0659deb9c03535fd61839e91d4d4d3e51ac71","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/5599b212d2f4466e1832a94e9932684aaa364587","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/86ddf8118123cb58a0fb8724cad6979c4069065b","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ad673e514b2793b8d5902f6ba6ab7e890dea23d5","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ea62dd1383913b5999f3d16ae99d411f41b528d4","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/f0bb3935470684306e4e04793a20ac4c4b08de0b","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-265688.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"}],"tags":["nvd"],"epss":0.00237,"epssPercentile":0.1494,"ingestedAt":"2026-07-30T06:53:08.880Z","slug":"CVE-2025-21640","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nsctp: sysctl: cookie_hmac_alg: avoid using current->nsproxy\n\nAs mentioned in a previous commit of this series, using the 'net'\nstructure via 'current' is not recommended for different reasons:\n\n- Inconsistency: getting info from the reader's/writer's netns vs only\n  from the opener's netns.\n\n- current->nsproxy can be NULL in some cases, resulting in an 'Oops'\n  (null-ptr-deref), e.g. when the current task is exiting, as spotted by\n  syzbot [1] using acct(2).\n\nThe 'net' structure can be obtained from the table->data using\ncontainer_of().\n\nNote that table->data could also be used directly, as this is the only\nmember needed from the 'net' structure, but that would increase the size\nof this fix, to use '*data' everywhere 'net->sctp.sctp_hmac_alg' is\nused.\n\n## Affected\n\n- `linux_kernel >= 3.8, < 6.1.125`\n- `linux_kernel >= 6.2, < 6.6.72`\n- `linux_kernel >= 6.7, < 6.12.10`\n- `linux_kernel = 6.13`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `linux_kernel 6.12.10`","depth":"twilight","depthScore":39,"depthScoreParts":{"impact":39.1,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}