CVE-2026-72068 (GCVE-0-2026-72068)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:52 – Updated: 2026-08-17 05:07
VLAI
Title
posix-cpu-timers: Use u64 multiplication in update_rlimit_cpu()
Summary
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.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4 , < feb5c87c8514444ba891b75a5a3eae57c64edaf8 (git)
Affected: 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4 , < 384628d6cdde0fcd76868606fad3ad8293100afb (git)
Affected: 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4 , < 1fafc4d9b411645eb34de43362b966dc8fb3e263 (git)
Affected: 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4 , < cff8281bacd2866767e6194c3079d33b6c5a74f4 (git)
Affected: 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4 , < edf6babb9edd2d3e19229ade339081f439d4f478 (git)
Affected: 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4 , < ea6a188ee805e841a0e242f14d15953e0dfa74bb (git)
Affected: 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4 , < 571e1f10b5996ba3e4dc63ea77de4aa309c384ce (git)
Affected: 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4 , < 26aff38fefb1d6cd87e22525f41cc8f1aa61b24f (git)
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Linux Linux Affected: 4.11
Unaffected: 0 , < 4.11 (semver)
Unaffected: 5.10.261 , ≤ 5.10.* (semver)
Unaffected: 5.15.212 , ≤ 5.15.* (semver)
Unaffected: 6.1.178 , ≤ 6.1.* (semver)
Unaffected: 6.6.145 , ≤ 6.6.* (semver)
Unaffected: 6.12.97 , ≤ 6.12.* (semver)
Unaffected: 6.18.40 , ≤ 6.18.* (semver)
Unaffected: 7.1.5 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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          "value": "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 * 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 \u003e 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 \u003e= 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."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:07:35.943Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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    "cveId": "CVE-2026-72068",
    "datePublished": "2026-08-15T05:52:21.007Z",
    "dateReserved": "2026-08-09T03:40:39.903Z",
    "dateUpdated": "2026-08-17T05:07:35.943Z",
    "state": "PUBLISHED"
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            "value": "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 * 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 \u003e 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 \u003e= 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."
          }
        ],
        "id": "CVE-2026-72068",
        "lastModified": "2026-08-17T06:18:05.303",
        "metrics": {},
        "published": "2026-08-15T06:21:16.467",
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        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
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    },
    "redhat_vex": {
      "aggregate_severity": "Low",
      "current_release_date": "2026-08-19T05:25:27+00:00",
      "cve": "CVE-2026-72068",
      "id": "CVE-2026-72068",
      "initial_release_date": "2026-08-15T00:00:00+00:00",
      "product_status:known_affected": "232",
      "product_status:known_not_affected": "42",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: posix-cpu-timers: Use u64 multiplication in update_rlimit_cpu()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-72068.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-10T02:10:19Z",
      "cve": "CVE-2026-72068",
      "id": "CVE-2026-72068",
      "initial_release_date": "2026-08-28T01:01:34Z",
      "product_status:known_affected": "315",
      "product_status:known_not_affected": "47",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-72068",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-72068.json",
      "version": "3"
    }
  }
}



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Detection rules are retrieved from Rulezet.


Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.