CVE-2026-31574

#include <stdio.h> #include <time.h> #include <signal.h> #include <unistd.h> #include <stdlib.h> // Conceptual Proof of Concept for CVE-2026-31574 // This code attempts to trigger the logic error by manipulating timers. void handler(int sig) { printf("Timer signal received\n"); } int main() { timer_t timerid; struct sigevent sev; struct itimerspec its; struct sigaction sa; // Establish handler for timer signal sa.sa_flags = SA_SIGINFO; sa.sa_handler = handler; sigemptyset(&sa.sa_mask); sigaction(SIGRTMIN, &sa, NULL); // Create the timer sev.sigev_notify = SIGEV_SIGNAL; sev.sigev_signo = SIGRTMIN; sev.sigev_value.sival_ptr = &timerid; timer_create(CLOCK_REALTIME, &sev, &timerid); // Arm the timer with a very long duration to simulate the 'far out' event its.it_value.tv_sec = 100000; // Far out in the future its.it_value.tv_nsec = 0; its.it_interval.tv_sec = 0; its.it_interval.tv_nsec = 0; timer_settime(timerid, 0, &its, NULL); printf("Timer armed with long duration. Attempting to trigger state change...\n"); // In a real exploit scenario, specific interaction with the clockevent // device (e.g., triggering suspend/resume or changing clock source) // would be required to hit the missing reset of next_event_forced. sleep(1); // Cleanup timer_delete(timerid); return 0; }

{"cve": {"id": "CVE-2026-31574", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-04-24T15:16:32.020", "lastModified": "2026-05-19T14:22:43.347", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nclockevents: Add missing resets of the next_event_forced flag\n\nThe prevention mechanism against timer interrupt starvation missed to reset\nthe next_event_forced flag in a couple of places:\n\n - When the clock event state changes. That can cause the flag to be\n stale over a shutdown/startup sequence\n\n - When a non-forced event is armed, which then prevents rearming before\n that event. If that event is far out in the future this will cause\n missed timer interrupts.\n\n - In the suspend wakeup handler.\n\nThat led to stalls which have been reported by several people.\n\nAdd the missing resets, which fixes the problems for the reporters."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "baseScore": 5.5, "baseSeverity": "MEDIUM", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "NVD-CWE-noinfo"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:-:*:*:*:*:*:*", "matchCriteriaId": "EF897730-3F1E-47A2-8B07-22535202C487"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/4096fd0e8eaea13ebe5206700b33f49635ae18e5", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/9401b593fa48218d2667df1610b0ebc518554880", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}