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Linux KernelOperating system · Linux

CVE-2025-37929

MEDIUM · 5.5 CVSS v3.1 Published 2025-05-20
Fix available
A fix is available. Upgrade to 6.1.138 / 6.6.90 or later.
See remediation →
57/100
Remediation priority · Elevated
Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis
How this class of weakness works · CWE-476

The code follows a pointer that is null, crashing the process. An attacker who can reliably trigger it turns the crash into a denial of service. The fix is checking for null before use and handling the failure path gracefully.

General guidance for the null pointer dereference class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Linux KernelOperating system
Affected:>= 6.1.135, < 6.1.138>= 6.6.88, < 6.6.90>= 6.12.24, < 6.12.28>= 6.13.12, < 6.14>= 6.14.3, < 6.14.6= 5.15.181= 6.15
Debian LinuxOperating system
Affected:= 11.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 6.1.138 / 6.6.90 / 6.12.28 or later
Fixed in 6.1.1386.6.906.12.28
Vendor patch git.kernel.org →
Recommended fix High confidence

Linux Kernel 6.1.138+ / 6.6.90+ / 6.12.28+ / 6.14 (depending on your current branch)

  1. Identify the currently running Linux kernel version using 'uname -r' or 'cat /proc/version'
  2. Determine which kernel branch your version belongs to (6.1.x, 6.6.x, 6.12.x, or 6.13.x)
  3. Upgrade the kernel to the fixed version for your branch: 6.1.138+, 6.6.90+, 6.12.28+, or 6.14+
  4. Reboot the system to load the patched kernel
  5. Verify the fix is applied by checking the kernel version and confirming the sentinel entries are present in the Spectre-BHB MIDR arrays
Caveat Kernel upgrades may require matching module rebuilds; ensure compatible drivers and modules are available for the new kernel version

Generated from the published advisory — verify against the referenced sources before acting.

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $2,850. Get the upgrade done

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-37929 in production — separate from our analysis above.

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What this is

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  • Version or environment caveats, and links to real fixes
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