{"id":"CVE-2025-21683","title":"bpf: Fix bpf_sk_select_reuseport() memory leak","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix bpf_sk_select_reuseport() memory leak\n\nAs pointed out in the original comment, lookup in sockmap can return a TCP\nESTABLISHED socket. Such TCP socket may have …","severity":"medium","cvss":5.5,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","cvssSource":"adp","vendor":"Linux","product":"Linux","affected":["Linux >= 64d85290d79c0677edb5a8ee2295b36c022fa5df < bb36838dac7bb334a3f3d7eb29875593ec9473fc","Linux >= 64d85290d79c0677edb5a8ee2295b36c022fa5df < 0ab52a8ca6e156a64c51b5e7456cac9a0ebfd9bf","Linux >= 64d85290d79c0677edb5a8ee2295b36c022fa5df < d0a3b3d1176d39218b8edb2a2d03164942ab9ccd","Linux >= 64d85290d79c0677edb5a8ee2295b36c022fa5df < b02e70be498b138e9c21701c2f33f4018ca7cd5e","Linux >= 64d85290d79c0677edb5a8ee2295b36c022fa5df < cccd51dd22574216e64e5d205489e634f86999f3","Linux >= 64d85290d79c0677edb5a8ee2295b36c022fa5df < b3af60928ab9129befa65e6df0310d27300942bf","Linux 5.8"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2025-10-01T19:51:47.465503Z"},"published":"2025-01-31","updated":"2026-10-15","sourceUpdated":"2026-10-15T01:03:01.511Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2025-21683","references":[{"url":"https://git.kernel.org/stable/c/bb36838dac7bb334a3f3d7eb29875593ec9473fc"},{"url":"https://git.kernel.org/stable/c/0ab52a8ca6e156a64c51b5e7456cac9a0ebfd9bf"},{"url":"https://git.kernel.org/stable/c/d0a3b3d1176d39218b8edb2a2d03164942ab9ccd"},{"url":"https://git.kernel.org/stable/c/b02e70be498b138e9c21701c2f33f4018ca7cd5e"},{"url":"https://git.kernel.org/stable/c/cccd51dd22574216e64e5d205489e634f86999f3"},{"url":"https://git.kernel.org/stable/c/b3af60928ab9129befa65e6df0310d27300942bf"}],"tags":["cve.org"],"epss":0.00224,"epssPercentile":0.12919,"ingestedAt":"2026-10-15T04:46:37.355Z","slug":"CVE-2025-21683","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix bpf_sk_select_reuseport() memory leak\n\nAs pointed out in the original comment, lookup in sockmap can return a TCP\nESTABLISHED socket. Such TCP socket may have had SO_ATTACH_REUSEPORT_EBPF\nset before it was ESTABLISHED. In other words, a non-NULL sk_reuseport_cb\ndoes not imply a non-refcounted socket.\n\nDrop sk's reference in both error paths.\n\nunreferenced object 0xffff888101911800 (size 2048):\n  comm \"test_progs\", pid 44109, jiffies 4297131437\n  hex dump (first 32 bytes):\n    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................\n    80 00 01 00 00 00 00 00 00 00 00 00 00 00 00 00  ................\n  backtrace (crc 9336483b):\n    __kmalloc_noprof+0x3bf/0x560\n    __reuseport_alloc+0x1d/0x40\n    reuseport_alloc+0xca/0x150\n    reuseport_attach_prog+0x87/0x140\n    sk_reuseport_attach_bpf+0xc8/0x100\n    sk_setsockopt+0x1181/0x1990\n    do_sock_setsockopt+0x12b/0x160\n    __sys_setsockopt+0x7b/0xc0\n    __x64_sys_setsockopt+0x1b/0x30\n    do_syscall_64+0x93/0x180\n    entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\n## Affected\n\n- `Linux >= 64d85290d79c0677edb5a8ee2295b36c022fa5df < bb36838dac7bb334a3f3d7eb29875593ec9473fc`\n- `Linux >= 64d85290d79c0677edb5a8ee2295b36c022fa5df < 0ab52a8ca6e156a64c51b5e7456cac9a0ebfd9bf`\n- `Linux >= 64d85290d79c0677edb5a8ee2295b36c022fa5df < d0a3b3d1176d39218b8edb2a2d03164942ab9ccd`\n- `Linux >= 64d85290d79c0677edb5a8ee2295b36c022fa5df < b02e70be498b138e9c21701c2f33f4018ca7cd5e`\n- `Linux >= 64d85290d79c0677edb5a8ee2295b36c022fa5df < cccd51dd22574216e64e5d205489e634f86999f3`\n- `Linux >= 64d85290d79c0677edb5a8ee2295b36c022fa5df < b3af60928ab9129befa65e6df0310d27300942bf`\n- `Linux 5.8`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":30.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}