{"id":"CVE-2025-21758","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: mcast: add RCU protection to mld_newpack()\n\nmld_newpack() can be called without RTNL or RCU being held.\n\nNote that we no longer can use sock_alloc_send_skb() beca…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: mcast: add RCU protection to mld_newpack()\n\nmld_newpack() can be called without RTNL or RCU being held.\n\nNote that we no longer can use sock_alloc_send_skb() beca…","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 >= 2.6.26, < 5.15.179","linux_kernel >= 5.16, < 6.1.129","linux_kernel >= 6.2, < 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":"2025-02-27","updated":"2026-10-15","sourceUpdated":"2026-10-15T02:17:32.710","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2025-21758","references":[{"url":"https://git.kernel.org/stable/c/1b91c597b0214b1b462eb627ec02658c944623f2","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/25195f9d5ffcc8079ad743a50c0409dbdc48d98a","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/29fa42197f26a97cde29fa8c40beddf44ea5c8f3","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/a527750d877fd334de87eef81f1cb5f0f0ca3373","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/d60d493b0e65647e0335e6a7c4547abcea7df8e9","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/e8af3632a7f2da83e27b083f787bced1faba00b1","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://lists.debian.org/debian-lts-announce/2025/03/msg00028.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-019113.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-082556.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-457936.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-784472.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"}],"tags":["nvd","cve.org"],"epss":0.1693,"epssPercentile":0.97042,"ingestedAt":"2026-07-14T13:36:55.640Z","slug":"CVE-2025-21758","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nipv6: mcast: add RCU protection to mld_newpack()\n\nmld_newpack() can be called without RTNL or RCU being held.\n\nNote that we no longer can use sock_alloc_send_skb() because\nipv6.igmp_sk uses GFP_KERNEL allocations which can sleep.\n\nInstead use alloc_skb() and charge the net->ipv6.igmp_sk\nsocket under RCU protection.\n\n## Affected\n\n- `linux_kernel >= 2.6.26, < 5.15.179`\n- `linux_kernel >= 5.16, < 6.1.129`\n- `linux_kernel >= 6.2, < 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":46,"depthScoreParts":{"impact":42.9,"likelihood":3.4,"exploitation":0,"ransomware":0},"changes":[{"seq":221480,"id":"CVE-2025-21758","ts":1792035218832,"field":"cvss","old":"5.5","new":"7.8"},{"seq":221479,"id":"CVE-2025-21758","ts":1792035218832,"field":"severity","old":"medium","new":"high"}]}