{"id":"CVE-2026-98584","title":"net/sched: fix potential stack infoleak in em_text_dump()","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: fix potential stack infoleak in em_text_dump()\n\nem_text_dump() allocates struct tcf_em_text on the stack without zeroing\nit.  strscpy() writes the algorithm …","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= b04202d6065cba5dfd51fb9866400b25573eac67 < 9923e1c537f91f3530b52d4efce85f3d9c131bf8","Linux >= b04202d6065cba5dfd51fb9866400b25573eac67 < 0b160417826d22f24fc31a5b9cfae3b14aa70f76","Linux >= b04202d6065cba5dfd51fb9866400b25573eac67 < 9c572a83037a7dcd653ba3a9cc468c16b857d0c9","Linux 6.17"],"published":"2026-10-18","updated":"2026-10-18","sourceUpdated":"2026-10-18T15:18:57.204Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-98584","references":[{"url":"https://git.kernel.org/stable/c/9923e1c537f91f3530b52d4efce85f3d9c131bf8"},{"url":"https://git.kernel.org/stable/c/0b160417826d22f24fc31a5b9cfae3b14aa70f76"},{"url":"https://git.kernel.org/stable/c/9c572a83037a7dcd653ba3a9cc468c16b857d0c9"}],"tags":["cve.org"],"ingestedAt":"2026-10-18T15:45:12.253Z","slug":"CVE-2026-98584","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: fix potential stack infoleak in em_text_dump()\n\nem_text_dump() allocates struct tcf_em_text on the stack without zeroing\nit.  strscpy() writes the algorithm name and a NUL terminator into\nconf.algo[], leaving the remaining bytes uninitialised.  nla_put_nohdr()\nthen copies the full struct to the netlink response.\n\nKMSAN on Linux 7.2-rc6 reports two kernel-infoleak splats from this path,\none triggered via \"tc filter show\" and one via a raw RTM_GETTFILTER dump:\n\n  BUG: KMSAN: kernel-infoleak in _copy_to_iter+0x1c9/0x2620\n    nla_put_nohdr+0x83/0x130\n    em_text_dump+0x291/0x550\n  Local variable conf created at: em_text_dump+0x5d/0x550\n  Bytes 168-179 of 199 are uninitialized\n\nI am not certain whether this constitutes a real security problem in\npractice: the test was conducted in a controlled KMSAN environment and\nthe leaked stack bytes may or may not carry sensitive data on actual\nproduction kernels.  I am reporting it because KMSAN flagged it as a\nkernel-infoleak and the fix is straightforward.  I can provide a\nuserspace reproducer on request.\n\nThe original code used strncpy() which zero-pads to the destination size.\nCommit b04202d6065c (\"net/sched: replace strncpy with strscpy\") replaced\nit with strscpy(), which does not pad, creating this condition.\nZero-initialising the struct closes it.\n\n## Affected\n\n- `Linux >= b04202d6065cba5dfd51fb9866400b25573eac67 < 9923e1c537f91f3530b52d4efce85f3d9c131bf8`\n- `Linux >= b04202d6065cba5dfd51fb9866400b25573eac67 < 0b160417826d22f24fc31a5b9cfae3b14aa70f76`\n- `Linux >= b04202d6065cba5dfd51fb9866400b25573eac67 < 9c572a83037a7dcd653ba3a9cc468c16b857d0c9`\n- `Linux 6.17`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}