Description

In the Linux kernel, the following vulnerability has been resolved:

book3s64/radix : Align section vmemmap start address to PAGE_SIZE

A vmemmap altmap is a device-provided region used to provide
backing storage for struct pages. For each namespace, the altmap
should belong to that same namespace. If the namespaces are
created unaligned, there is a chance that the section vmemmap
start address could also be unaligned. If the section vmemmap
start address is unaligned, the altmap page allocated from the
current namespace might be used by the previous namespace also.
During the free operation, since the altmap is shared between two
namespaces, the previous namespace may detect that the page does
not belong to its altmap and incorrectly assume that the page is a
normal page. It then attempts to free the normal page, which leads
to a kernel crash.

Kernel attempted to read user page (18) - exploit attempt? (uid: 0)
BUG: Kernel NULL pointer dereference on read at 0x00000018
Faulting instruction address: 0xc000000000530c7c
Oops: Kernel access of bad area, sig: 11 [#1]
LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA pSeries
CPU: 32 PID: 2104 Comm: ndctl Kdump: loaded Tainted: G W
NIP: c000000000530c7c LR: c000000000530e00 CTR: 0000000000007ffe
REGS: c000000015e57040 TRAP: 0300 Tainted: G W
MSR: 800000000280b033 CR: 84482404
CFAR: c000000000530dfc DAR: 0000000000000018 DSISR: 40000000 IRQMASK: 0
GPR00: c000000000530e00 c000000015e572e0 c000000002c5cb00 c00c00...

Known Exploited

🚨 Marked as known exploited on May 20th, 2025 (11 days ago).

Classification

CVE ID: CVE-2025-37922

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.02% (probability of being exploited)

EPSS Percentile: 4.65% (scored less or equal to compared to others)

EPSS Date: 2025-05-30 (when was this score calculated)

References

https://nvd.nist.gov/vuln/detail/CVE-2025-37922
https://git.kernel.org/stable/c/9a8d4d7072d4df108479b1adc4b0840e96f6f61d
https://git.kernel.org/stable/c/7f5476d80f2cb364701cd1fa138a14b241ca99e9
https://git.kernel.org/stable/c/400be767deaf31a073c6d14c5d151ae5ac2a60e2
https://git.kernel.org/stable/c/9cf7e13fecbab0894f6986fc6986ab2eba8de52e

Timeline