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CVE-2026-72068

UnknownEPSS 0.22%

Last modified

CVE-2026-72068 is a vulnerability of currently unknown severity. 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. EPSS estimates a 0.22% chance of exploitation in the next 30 days.

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.

Metrics

EPSS Probability
0.22%

12.8th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4, < feb5c87c8514444ba891b75a5a3eae57c64edaf8; >= 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4, < 384628d6cdde0fcd76868606fad3ad8293100afb; >= 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4, < 1fafc4d9b411645eb34de43362b966dc8fb3e263; >= 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4, < cff8281bacd2866767e6194c3079d33b6c5a74f4; >= 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4, < edf6babb9edd2d3e19229ade339081f439d4f478; >= 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4, < ea6a188ee805e841a0e242f14d15953e0dfa74bb; >= 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4, < 571e1f10b5996ba3e4dc63ea77de4aa309c384ce; >= 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4, < 26aff38fefb1d6cd87e22525f41cc8f1aa61b24f
LinuxLinux4.11

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-72068?
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.
How severe is CVE-2026-72068?
Severity scoring for CVE-2026-72068 is pending analysis. The EPSS model estimates a 0.22% probability of exploitation in the next 30 days.
How do I fix CVE-2026-72068?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST