posix-cpu-timers: Use u64 multiplication in update_rlimit_cpu()
Summary
| CVE | CVE-2026-72068 |
|---|---|
| State | PUBLISHED |
| Assigner | Linux |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-08-15 06:21:16 UTC |
| Updated | 2026-08-17 06:18:05 UTC |
| Description | In the Linux kernel, the following vulnerability has been resolved: posix-cpu-timers: Use u64 multiplication in update_rlimit_cpu() update_rlimit_cpu() converts the RLIMIT_CPU value to nanoseconds with u64 nsecs = rlim_new * NSEC_PER_SEC; On 32-bit kernels both rlim_new (unsigned long) and NSEC_PER_SEC (1000000000L) are 32-bit, so the multiplication is performed in unsigned long and truncated for rlim_new > 4 seconds before being widened to u64. The same file already casts to u64 for the matching computation in check_process_timers(): u64 softns = (u64)soft * NSEC_PER_SEC; As a result, the truncated value is installed into the CPUCLOCK_PROF expiry cache (nextevt), causing the process CPU timer to be programmed to fire prematurely for any RLIMIT_CPU soft limit >= 5 seconds. The actual SIGXCPU/SIGKILL decision in check_process_timers() already casts to u64 and is therefore correct, so limit enforcement is not broken; only the expiry-cache programming is wrong. Apply the same cast here so both paths convert rlim_cur identically. 64-bit kernels are unaffected. |
Risk And Classification
EPSS: 0.002200000 probability, percentile 0.127060000 (date 2026-08-17)
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Linux | Linux | affected 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4 feb5c87c8514444ba891b75a5a3eae57c64edaf8 git | Not specified |
| CNA | Linux | Linux | affected 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4 384628d6cdde0fcd76868606fad3ad8293100afb git | Not specified |
| CNA | Linux | Linux | affected 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4 1fafc4d9b411645eb34de43362b966dc8fb3e263 git | Not specified |
| CNA | Linux | Linux | affected 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4 cff8281bacd2866767e6194c3079d33b6c5a74f4 git | Not specified |
| CNA | Linux | Linux | affected 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4 edf6babb9edd2d3e19229ade339081f439d4f478 git | Not specified |
| CNA | Linux | Linux | affected 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4 ea6a188ee805e841a0e242f14d15953e0dfa74bb git | Not specified |
| CNA | Linux | Linux | affected 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4 571e1f10b5996ba3e4dc63ea77de4aa309c384ce git | Not specified |
| CNA | Linux | Linux | affected 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4 26aff38fefb1d6cd87e22525f41cc8f1aa61b24f git | Not specified |
| CNA | Linux | Linux | affected 4.11 | Not specified |
| CNA | Linux | Linux | unaffected 4.11 semver | Not specified |
| CNA | Linux | Linux | unaffected 5.10.261 5.10.* semver | Not specified |
| CNA | Linux | Linux | unaffected 5.15.212 5.15.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.1.178 6.1.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.6.145 6.6.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.12.97 6.12.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.18.40 6.18.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.1.5 7.1.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.2 * original_commit_for_fix | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| git.kernel.org/stable/c/ea6a188ee805e841a0e242f14d15953e0dfa74bb | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/571e1f10b5996ba3e4dc63ea77de4aa309c384ce | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/edf6babb9edd2d3e19229ade339081f439d4f478 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/feb5c87c8514444ba891b75a5a3eae57c64edaf8 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/384628d6cdde0fcd76868606fad3ad8293100afb | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/cff8281bacd2866767e6194c3079d33b6c5a74f4 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/26aff38fefb1d6cd87e22525f41cc8f1aa61b24f | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/1fafc4d9b411645eb34de43362b966dc8fb3e263 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.