n the Linux kernel, the following vulnerability has been resolved: perf/core: Prevent VMA split of buffer mappings The perf mmap code is careful about mmap()'ing the user page with the ringbuffer and additionally the auxiliary buffer, when the event supports it. Once the first mapping is established, subsequent mapping have to use the same offset and the same size in both cases. The reference counting for the ringbuffer and the auxiliary buffer depends on this being correct. Though perf does not prevent that a related mapping is split via mmap(2), munmap(2) or mremap(2). A split of a VMA results in perf_mmap_open() calls, which take reference counts, but then the subsequent perf_mmap_close() calls are not longer fulfilling the offset and size checks. This leads to reference count leaks. As perf already has the requirement for subsequent mappings to match the initial mapping, the obvious consequence is that VMA splits, caused by resizing of a mapping or partial unmapping, have to be prevented. Implement the vm_operations_struct::may_split() callback and return unconditionally -EINVAL. That ensures that the mapping offsets and sizes cannot be changed after the fact. Remapping to a different fixed address with the same size is still possible as it takes the references for the new mapping and drops those of the old mapping.
Configuration 1 (hide)
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Configuration 2 (hide)
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08 Jan 2026, 21:03
| Type | Values Removed | Values Added |
|---|---|---|
| First Time |
Debian
Linux linux Kernel Linux Debian debian Linux |
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| CWE | NVD-CWE-noinfo | |
| CPE | cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
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| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 7.8 |
| References | () https://git.kernel.org/stable/c/3bd518cc7ea61076bcd725e36ff0e690754977c0 - Patch | |
| References | () https://git.kernel.org/stable/c/65311aad4c808bedad0c05d9bb8b06c47dae73eb - Patch | |
| References | () https://git.kernel.org/stable/c/6757a31a8e295ae4f01717a954afda173f25a121 - Patch | |
| References | () https://git.kernel.org/stable/c/7b84cb58d1f0aa07656802eae24689566e5f5b1b - Patch | |
| References | () https://git.kernel.org/stable/c/b024d7b56c77191cde544f838debb7f8451cd0d6 - Patch | |
| References | () https://git.kernel.org/stable/c/d52451a9210f2e5a079ba052918c93563518a9ff - Patch | |
| References | () https://git.kernel.org/stable/c/e4346ffec2c44d6b0be834d59b20632b5bb5729e - Patch | |
| References | () https://git.kernel.org/stable/c/e529888b7e8092912dd8789bdfc76685ccd2ff5f - Patch | |
| References | () https://git.kernel.org/stable/c/ff668930871e0198c7f4e325058b8b7c286787bd - Patch | |
| References | () https://www.zerodayinitiative.com/advisories/ZDI-25-873/ - Third Party Advisory | |
| References | () https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html - Third Party Advisory, Mailing List | |
| References | () https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html - Third Party Advisory, Mailing List |
03 Nov 2025, 18:16
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| References |
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10 Oct 2025, 16:15
| Type | Values Removed | Values Added |
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28 Aug 2025, 15:15
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| New CVE |
Published : 2025-08-19 17:15
Updated : 2026-01-08 21:03
NVD link : CVE-2025-38563
Mitre link : CVE-2025-38563
CVE.ORG link : CVE-2025-38563
JSON object : View