{"id":"CVE-2026-72068","title":"posix-cpu-timers: Use u64 multiplication in update_rlimit_cpu()","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nposix-cpu-timers: Use u64 multiplication in update_rlimit_cpu()\n\nupdate_rlimit_cpu() converts the RLIMIT_CPU value to nanoseconds with\n\n        u64 nsecs = rlim_new * N…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4 < feb5c87c8514444ba891b75a5a3eae57c64edaf8","Linux >= 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4 < 384628d6cdde0fcd76868606fad3ad8293100afb","Linux >= 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4 < 1fafc4d9b411645eb34de43362b966dc8fb3e263","Linux >= 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4 < cff8281bacd2866767e6194c3079d33b6c5a74f4","Linux >= 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4 < edf6babb9edd2d3e19229ade339081f439d4f478","Linux >= 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4 < ea6a188ee805e841a0e242f14d15953e0dfa74bb","Linux >= 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4 < 571e1f10b5996ba3e4dc63ea77de4aa309c384ce","Linux >= 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4 < 26aff38fefb1d6cd87e22525f41cc8f1aa61b24f","Linux 4.11"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-11-06T16:51:04.940462Z"},"published":"2026-08-15","updated":"2026-11-06","sourceUpdated":"2026-11-06T16:55:19.267Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-72068","references":[{"url":"https://git.kernel.org/stable/c/feb5c87c8514444ba891b75a5a3eae57c64edaf8"},{"url":"https://git.kernel.org/stable/c/384628d6cdde0fcd76868606fad3ad8293100afb"},{"url":"https://git.kernel.org/stable/c/1fafc4d9b411645eb34de43362b966dc8fb3e263"},{"url":"https://git.kernel.org/stable/c/cff8281bacd2866767e6194c3079d33b6c5a74f4"},{"url":"https://git.kernel.org/stable/c/edf6babb9edd2d3e19229ade339081f439d4f478"},{"url":"https://git.kernel.org/stable/c/ea6a188ee805e841a0e242f14d15953e0dfa74bb"},{"url":"https://git.kernel.org/stable/c/571e1f10b5996ba3e4dc63ea77de4aa309c384ce"},{"url":"https://git.kernel.org/stable/c/26aff38fefb1d6cd87e22525f41cc8f1aa61b24f"}],"tags":["cve.org"],"epss":0.0022,"epssPercentile":0.12538,"ingestedAt":"2026-11-06T18:00:12.599Z","slug":"CVE-2026-72068","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nposix-cpu-timers: Use u64 multiplication in update_rlimit_cpu()\n\nupdate_rlimit_cpu() converts the RLIMIT_CPU value to nanoseconds with\n\n        u64 nsecs = rlim_new * NSEC_PER_SEC;\n\nOn 32-bit kernels both rlim_new (unsigned long) and NSEC_PER_SEC\n(1000000000L) are 32-bit, so the multiplication is performed in unsigned\nlong and truncated for rlim_new > 4 seconds before being widened to u64.\n\nThe same file already casts to u64 for the matching computation in\ncheck_process_timers():\n\n        u64 softns = (u64)soft * NSEC_PER_SEC;\n\nAs a result, the truncated value is installed into the CPUCLOCK_PROF\nexpiry cache (nextevt), causing the process CPU timer to be programmed\nto fire prematurely for any RLIMIT_CPU soft limit >= 5 seconds. The\nactual SIGXCPU/SIGKILL decision in check_process_timers() already casts\nto u64 and is therefore correct, so limit enforcement is not broken;\nonly the expiry-cache programming is wrong. Apply the same cast here so\nboth paths convert rlim_cur identically.\n\n64-bit kernels are unaffected.\n\n## Affected\n\n- `Linux >= 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4 < feb5c87c8514444ba891b75a5a3eae57c64edaf8`\n- `Linux >= 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4 < 384628d6cdde0fcd76868606fad3ad8293100afb`\n- `Linux >= 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4 < 1fafc4d9b411645eb34de43362b966dc8fb3e263`\n- `Linux >= 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4 < cff8281bacd2866767e6194c3079d33b6c5a74f4`\n- `Linux >= 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4 < edf6babb9edd2d3e19229ade339081f439d4f478`\n- `Linux >= 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4 < ea6a188ee805e841a0e242f14d15953e0dfa74bb`\n- `Linux >= 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4 < 571e1f10b5996ba3e4dc63ea77de4aa309c384ce`\n- `Linux >= 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4 < 26aff38fefb1d6cd87e22525f41cc8f1aa61b24f`\n- `Linux 4.11`\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":[]}