CVE-2026-23127

  1. Yack CVE
  2. Vulnerabilities (CVE)
  3. CVE-2026-23127
CVSS

No CVSS.

I

n the Linux kernel, the following vulnerability has been resolved: perf: Fix refcount warning on event->mmap_count increment When calling refcount_inc(&event->mmap_count) inside perf_mmap_rb(), the following warning is triggered: refcount_t: addition on 0; use-after-free. WARNING: lib/refcount.c:25 PoC: struct perf_event_attr attr = {0}; int fd = syscall(__NR_perf_event_open, &attr, 0, -1, -1, 0); mmap(NULL, 0x3000, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); int victim = syscall(__NR_perf_event_open, &attr, 0, -1, fd, PERF_FLAG_FD_OUTPUT); mmap(NULL, 0x3000, PROT_READ | PROT_WRITE, MAP_SHARED, victim, 0); This occurs when creating a group member event with the flag PERF_FLAG_FD_OUTPUT. The group leader should be mmap-ed and then mmap-ing the event triggers the warning. Since the event has copied the output_event in perf_event_set_output(), event->rb is set. As a result, perf_mmap_rb() calls refcount_inc(&event->mmap_count) when event->mmap_count = 0. Disallow the case when event->mmap_count = 0. This also prevents two events from updating the same user_page.

References
Link Resource
https://git.kernel.org/stable/c/23c0e4bd93d0b250775162faf456470485ac9fc7
https://git.kernel.org/stable/c/d06bf78e55d5159c1b00072e606ab924ffbbad35
Configurations

No configuration.

History

18 Feb 2026, 17:52

Type Values Removed Values Added
Summary
  • (es) En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta: perf: Corrección de la advertencia de refcount en el incremento de event->mmap_count Al llamar a refcount_inc(&event->mmap_count) dentro de perf_mmap_rb(), se activa la siguiente advertencia: refcount_t: adición en 0; uso después de liberación. ADVERTENCIA: lib/refcount.c:25 PoC: struct perf_event_attr attr = {0}; int fd = syscall(__NR_perf_event_open, &attr, 0, -1, -1, 0); mmap(NULL, 0x3000, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); int victim = syscall(__NR_perf_event_open, &attr, 0, -1, fd, PERF_FLAG_FD_OUTPUT); mmap(NULL, 0x3000, PROT_READ | PROT_WRITE, MAP_SHARED, victim, 0); Esto ocurre al crear un evento miembro de grupo con la bandera PERF_FLAG_FD_OUTPUT. El líder del grupo debe ser mapeado con mmap y luego mapear el evento con mmap activa la advertencia. Dado que el evento ha copiado el output_event en perf_event_set_output(), event->rb está establecido. Como resultado, perf_mmap_rb() llama a refcount_inc(&event->mmap_count) cuando event->mmap_count = 0. No permitir el caso cuando event->mmap_count = 0. Esto también evita que dos eventos actualicen la misma user_page.

14 Feb 2026, 15:16

Type Values Removed Values Added
New CVE
Information

Published : 2026-02-14 15:16

Updated : 2026-02-18 17:52

NVD link : CVE-2026-23127

Mitre link : CVE-2026-23127

CVE.ORG link : CVE-2026-23127

JSON object : View

Products Affected

No product.

CWE

No CWE.