CVE-2025-38563
What it is
In 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.
At a glance
- Exploitability
- Can be exploited locally on the machine with a low-privilege account. High risk of data exposure, data tampering, service disruption.
- Exploit odds
- 0.4% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.4% in the next 30 days (EPSS).
- Severity: 7.8 HIGH (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.4% · EPSS, next 30 days
- Record status
- Analyzed
Affected
- Linux Kernel < 5.4.297
- Linux Kernel < 5.10.241
- Linux Kernel < 5.15.190
- Linux Kernel < 6.1.148
- Linux Kernel < 6.6.102
- Linux Kernel < 6.12.42
- Linux Kernel < 6.15.10
- Linux Kernel < 6.16.1
Attack profile CVSS 3.1 · 7.8
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Raw vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2025-38563.md and follow it. Check whether this project is affected by CVE-2025-38563. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://git.kernel.org/stable/c/3bd518cc7ea61076bcd725e36ff0e690754977c0
- https://git.kernel.org/stable/c/65311aad4c808bedad0c05d9bb8b06c47dae73eb
- https://git.kernel.org/stable/c/6757a31a8e295ae4f01717a954afda173f25a121
- https://git.kernel.org/stable/c/7b84cb58d1f0aa07656802eae24689566e5f5b1b
- https://git.kernel.org/stable/c/b024d7b56c77191cde544f838debb7f8451cd0d6
- https://git.kernel.org/stable/c/d52451a9210f2e5a079ba052918c93563518a9ff
- https://git.kernel.org/stable/c/e4346ffec2c44d6b0be834d59b20632b5bb5729e
- https://git.kernel.org/stable/c/e529888b7e8092912dd8789bdfc76685ccd2ff5f
- https://git.kernel.org/stable/c/ff668930871e0198c7f4e325058b8b7c286787bd
References
- https://git.kernel.org/stable/c/3bd518cc7ea61076bcd725e36ff0e690754977c0
- https://git.kernel.org/stable/c/65311aad4c808bedad0c05d9bb8b06c47dae73eb
- https://git.kernel.org/stable/c/6757a31a8e295ae4f01717a954afda173f25a121
- https://git.kernel.org/stable/c/7b84cb58d1f0aa07656802eae24689566e5f5b1b
- https://git.kernel.org/stable/c/b024d7b56c77191cde544f838debb7f8451cd0d6
- https://git.kernel.org/stable/c/d52451a9210f2e5a079ba052918c93563518a9ff
- https://git.kernel.org/stable/c/e4346ffec2c44d6b0be834d59b20632b5bb5729e
- https://git.kernel.org/stable/c/e529888b7e8092912dd8789bdfc76685ccd2ff5f
- https://git.kernel.org/stable/c/ff668930871e0198c7f4e325058b8b7c286787bd
- https://www.zerodayinitiative.com/advisories/ZDI-25-873/
- https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html
- https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html