Description

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

arm64: errata: Add missing sentinels to Spectre-BHB MIDR arrays

Commit a5951389e58d ("arm64: errata: Add newer ARM cores to the
spectre_bhb_loop_affected() lists") added some additional CPUs to the
Spectre-BHB workaround, including some new arrays for designs that
require new 'k' values for the workaround to be effective.

Unfortunately, the new arrays omitted the sentinel entry and so
is_midr_in_range_list() will walk off the end when it doesn't find a
match. With UBSAN enabled, this leads to a crash during boot when
is_midr_in_range_list() is inlined (which was more common prior to
c8c2647e69be ("arm64: Make  _midr_in_range_list() an exported
function")):

| Internal error: aarch64 BRK: 00000000f2000001 [#1] PREEMPT SMP
| pstate: 804000c5 (Nzcv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
| pc : spectre_bhb_loop_affected+0x28/0x30
| lr : is_spectre_bhb_affected+0x170/0x190
| [...]
| Call trace:
| spectre_bhb_loop_affected+0x28/0x30
| update_cpu_capabilities+0xc0/0x184
| init_cpu_features+0x188/0x1a4
| cpuinfo_store_boot_cpu+0x4c/0x60
| smp_prepare_boot_cpu+0x38/0x54
| start_kernel+0x8c/0x478
| __primary_switched+0xc8/0xd4
| Code: 6b09011f 54000061 52801080 d65f03c0 (d4200020)
| ---[ end trace 0000000000000000 ]---
| Kernel panic - not syncing: aarch64 BRK: Fatal exception

Add the missing sentinel entries.

Classification

CVE ID: CVE-2025-37929

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.07% (probability of being exploited)

EPSS Percentile: 21.81% (scored less or equal to compared to others)

EPSS Date: 2025-06-18 (when was this score calculated)

References

https://nvd.nist.gov/vuln/detail/CVE-2025-37929
https://git.kernel.org/stable/c/6266b3509b2c6ebf2f9daf2239ff8eb60c5f5bd3
https://git.kernel.org/stable/c/446289b8b36b2ee98dabf6388acbddcc33ed41be
https://git.kernel.org/stable/c/3821cae9bd5a99a42d3d0be1b58e41f072cd4c4c
https://git.kernel.org/stable/c/090c8714efe1c3c470301cc2f794c1ee2a57746c
https://git.kernel.org/stable/c/333579202f09e260e8116321df4c55f80a19b160
https://git.kernel.org/stable/c/fee4d171451c1ad9e8aaf65fc0ab7d143a33bd72

Timeline