{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-23127", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-01-13T15:37:45.970Z", "datePublished": "2026-02-14T15:09:56.237Z", "dateUpdated": "2026-02-14T15:09:56.237Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-02-14T15:09:56.237Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nperf: Fix refcount warning on event->mmap_count increment\n\nWhen calling refcount_inc(&event->mmap_count) inside perf_mmap_rb(), the\nfollowing warning is triggered:\n\n refcount_t: addition on 0; use-after-free.\n WARNING: lib/refcount.c:25\n\nPoC:\n\n struct perf_event_attr attr = {0};\n int fd = syscall(__NR_perf_event_open, &attr, 0, -1, -1, 0);\n mmap(NULL, 0x3000, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);\n int victim = syscall(__NR_perf_event_open, &attr, 0, -1, fd,\n PERF_FLAG_FD_OUTPUT);\n mmap(NULL, 0x3000, PROT_READ | PROT_WRITE, MAP_SHARED, victim, 0);\n\nThis occurs when creating a group member event with the flag\nPERF_FLAG_FD_OUTPUT. The group leader should be mmap-ed and then mmap-ing\nthe event triggers the warning.\n\nSince the event has copied the output_event in perf_event_set_output(),\nevent->rb is set. As a result, perf_mmap_rb() calls\nrefcount_inc(&event->mmap_count) when event->mmap_count = 0.\n\nDisallow the case when event->mmap_count = 0. This also prevents two\nevents from updating the same user_page."}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["kernel/events/core.c"], "versions": [{"version": "448f97fba9013ffa13f5dd82febd18836b189499", "lessThan": "23c0e4bd93d0b250775162faf456470485ac9fc7", "status": "affected", "versionType": "git"}, {"version": "448f97fba9013ffa13f5dd82febd18836b189499", "lessThan": "d06bf78e55d5159c1b00072e606ab924ffbbad35", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["kernel/events/core.c"], "versions": [{"version": "6.18", "status": "affected"}, {"version": "0", "lessThan": "6.18", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.8", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.19", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.18", "versionEndExcluding": "6.18.8"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.18", "versionEndExcluding": "6.19"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/23c0e4bd93d0b250775162faf456470485ac9fc7"}, {"url": "https://git.kernel.org/stable/c/d06bf78e55d5159c1b00072e606ab924ffbbad35"}], "title": "perf: Fix refcount warning on event->mmap_count increment", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nperf: Fix refcount warning on event->mmap_count increment\n\nWhen calling refcount_inc(&event->mmap_count) inside perf_mmap_rb(), the\nfollowing warning is triggered:\n\n refcount_t: addition on 0; use-after-free.\n WARNING: lib/refcount.c:25\n\nPoC:\n\n struct perf_event_attr attr = {0};\n int fd = syscall(__NR_perf_event_open, &attr, 0, -1, -1, 0);\n mmap(NULL, 0x3000, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);\n int victim = syscall(__NR_perf_event_open, &attr, 0, -1, fd,\n PERF_FLAG_FD_OUTPUT);\n mmap(NULL, 0x3000, PROT_READ | PROT_WRITE, MAP_SHARED, victim, 0);\n\nThis occurs when creating a group member event with the flag\nPERF_FLAG_FD_OUTPUT. The group leader should be mmap-ed and then mmap-ing\nthe event triggers the warning.\n\nSince the event has copied the output_event in perf_event_set_output(),\nevent->rb is set. As a result, perf_mmap_rb() calls\nrefcount_inc(&event->mmap_count) when event->mmap_count = 0.\n\nDisallow the case when event->mmap_count = 0. This also prevents two\nevents from updating the same user_page."}], "id": "CVE-2026-23127", "lastModified": "2026-02-14T15:16:07.963", "metrics": {}, "published": "2026-02-14T15:16:07.963", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/23c0e4bd93d0b250775162faf456470485ac9fc7"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/d06bf78e55d5159c1b00072e606ab924ffbbad35"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{}

{}