CVE-2026-72068: Linux kernel · posix-cpu-timers: Use u64 multiplication in update_rlimit_cpu()
Affects Linux kernelSource CVE Database V5
Not known to be exploited · fixed in feb5c87c8514444ba891b75a5a3eae57c64edaf8 : update Linux kernel when convenient.
Data as of 6 Nov 2026, 17:04 UTC
Rated by Threat Radar · CVSS not yet scored by NVD
Thin evidence
One scorer or none- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers cannot reliably automate steps 1–4 of the kill chain
- Technical impact
- Limited control over the software or limited information exposure
CISA SSVC assessment, 2026-11-06.
- Patch
- Available – fixed in feb5c87c8514444ba891b75a5a3eae57c64edaf8, edf6babb9edd2d3e19229ade339081f439d4f478, ea6a188ee805e841a0e242f14d15953e0dfa74bb +5
Exploitation evidence
Disclosed: evidence found.
CVE published 15 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 6 Nov 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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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.
References
- git.kernel.org/stable/c/feb5c87c8514444ba891b75a5a3eae57c64edaf8 (opens in a new tab)
- git.kernel.org/stable/c/384628d6cdde0fcd76868606fad3ad8293100afb (opens in a new tab)
- git.kernel.org/stable/c/1fafc4d9b411645eb34de43362b966dc8fb3e263 (opens in a new tab)
- git.kernel.org/stable/c/cff8281bacd2866767e6194c3079d33b6c5a74f4 (opens in a new tab)
- git.kernel.org/stable/c/edf6babb9edd2d3e19229ade339081f439d4f478 (opens in a new tab)
- git.kernel.org/stable/c/ea6a188ee805e841a0e242f14d15953e0dfa74bb (opens in a new tab)
- git.kernel.org/stable/c/571e1f10b5996ba3e4dc63ea77de4aa309c384ce (opens in a new tab)
- git.kernel.org/stable/c/26aff38fefb1d6cd87e22525f41cc8f1aa61b24f (opens in a new tab)