Linux Kernel up to 5.10.234/6.6.82/6.12.17/6.13.5 mm/early_ioremap.c early_memmap iteration

Summaryinfo

A vulnerability classified as problematic was found in Linux Kernel up to 5.10.234/6.6.82/6.12.17/6.13.5. This affects the function early_memmap of the file mm/early_ioremap.c. The manipulation results in iteration. This vulnerability is cataloged as CVE-2025-21872. There is no exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability classified as problematic has been found in Linux Kernel up to 5.10.234/6.6.82/6.12.17/6.13.5. Affected is the function early_memmap of the file mm/early_ioremap.c. The manipulation with an unknown input leads to a iteration vulnerability. CWE is classifying the issue as CWE-834. The product performs an iteration or loop without sufficiently limiting the number of times that the loop is executed. This is going to have an impact on availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: efi: Don't map the entire mokvar table to determine its size Currently, when validating the mokvar table, we (re)map the entire table on each iteration of the loop, adding space as we discover new entries. If the table grows over a certain size, this fails due to limitations of early_memmap(), and we get a failure and traceback: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 0 at mm/early_ioremap.c:139 __early_ioremap+0xef/0x220 ... Call Trace: <TASK> ? __early_ioremap+0xef/0x220 ? __warn.cold+0x93/0xfa ? __early_ioremap+0xef/0x220 ? report_bug+0xff/0x140 ? early_fixup_exception+0x5d/0xb0 ? early_idt_handler_common+0x2f/0x3a ? __early_ioremap+0xef/0x220 ? efi_mokvar_table_init+0xce/0x1d0 ? setup_arch+0x864/0xc10 ? start_kernel+0x6b/0xa10 ? x86_64_start_reservations+0x24/0x30 ? x86_64_start_kernel+0xed/0xf0 ? common_startup_64+0x13e/0x141 </TASK> ---[ end trace 0000000000000000 ]--- mokvar: Failed to map EFI MOKvar config table pa=0x7c4c3000, size=265187. Mapping the entire structure isn't actually necessary, as we don't ever need more than one entry header mapped at once. Changes efi_mokvar_table_init() to only map each entry header, not the entire table, when determining the table size. Since we're not mapping any data past the variable name, it also changes the code to enforce that each variable name is NUL terminated, rather than attempting to verify it in place.

The advisory is shared for download at git.kernel.org. This vulnerability is traded as CVE-2025-21872 since 12/29/2024. The exploitability is told to be difficult. There are known technical details, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 236983 (Ubuntu 24.04 LTS / 24.10 : Linux kernel vulnerabilities (USN-7521-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 5.10.235, 6.6.83, 6.12.18 or 6.13.6 eliminates this vulnerability. Applying the patch 46c0454ffb78ce9d3355a3cccac86383ea8ddd55/ea3f0b362dfe4ef885ef812bfaf4088176422c91/65f4aebb8127708ba668dd938e83b8558abfc5cd/97bd560b6cc4c26386a53b4881bf03e96f9ba03a/2b90e7ace79774a3540ce569e000388f8d22c9e0 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (236983) and CERT Bund (WID-SEC-2025-0649). Once again VulDB remains the best source for vulnerability data.

Affected

• Google Container-Optimized OS
• Debian Linux
• Amazon Linux 2
• Red Hat Enterprise Linux
• Ubuntu Linux
• SUSE Linux
• Oracle Linux
• SUSE openSUSE
• Dell Avamar
• Open Source Linux Kernel
• SolarWinds Security Event Manager
• Dell NetWorker
• Dell Secure Connect Gateway

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 5.10.234
• 6.6.0
• 6.6.1
• 6.6.2
• 6.6.3
• 6.6.4
• 6.6.5
• 6.6.6
• 6.6.7
• 6.6.8
• 6.6.9
• 6.6.10
• 6.6.11
• 6.6.12
• 6.6.13
• 6.6.14
• 6.6.15
• 6.6.16
• 6.6.17
• 6.6.18
• 6.6.19
• 6.6.20
• 6.6.21
• 6.6.22
• 6.6.23
• 6.6.24
• 6.6.25
• 6.6.26
• 6.6.27
• 6.6.28
• 6.6.29
• 6.6.30
• 6.6.31
• 6.6.32
• 6.6.33
• 6.6.34
• 6.6.35
• 6.6.36
• 6.6.37
• 6.6.38
• 6.6.39
• 6.6.40
• 6.6.41
• 6.6.42
• 6.6.43
• 6.6.44
• 6.6.45
• 6.6.46
• 6.6.47
• 6.6.48
• 6.6.49
• 6.6.50
• 6.6.51
• 6.6.52
• 6.6.53
• 6.6.54
• 6.6.55
• 6.6.56
• 6.6.57
• 6.6.58
• 6.6.59
• 6.6.60
• 6.6.61
• 6.6.62
• 6.6.63
• 6.6.64
• 6.6.65
• 6.6.66
• 6.6.67
• 6.6.68
• 6.6.69
• 6.6.70
• 6.6.71
• 6.6.72
• 6.6.73
• 6.6.74
• 6.6.75
• 6.6.76
• 6.6.77
• 6.6.78
• 6.6.79
• 6.6.80
• 6.6.81
• 6.6.82
• 6.12.0
• 6.12.1
• 6.12.2
• 6.12.3
• 6.12.4
• 6.12.5
• 6.12.6
• 6.12.7
• 6.12.8
• 6.12.9
• 6.12.10
• 6.12.11
• 6.12.12
• 6.12.13
• 6.12.14
• 6.12.15
• 6.12.16
• 6.12.17
• 6.13.0
• 6.13.1
• 6.13.2
• 6.13.3
• 6.13.4
• 6.13.5

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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CPE 2.2info

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Exploitinginfo

Threat Intelligenceinfo

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Entryinfo

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