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CVE-2025-21872— efi: Don't map the entire mokvar table to determine its size

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于未正确处理mokvar表大小计算，可能导致内存映射失败。

AI Predicted 5.3 Difficulty: Trivial EPSS 0.21% · P10

Possible ATT&CK Techniques 1 AI

T1003 · OS Credential Dumping

Affected Version Matrix 12

VendorProduct Version RangeStatus
Linux Linux 58c909022a5a56cd1d9e89c8c5461fd1f6a27bb5< 46c0454ffb78ce9d3355a3cccac86383ea8ddd55 affected
58c909022a5a56cd1d9e89c8c5461fd1f6a27bb5< ea3f0b362dfe4ef885ef812bfaf4088176422c91 affected
58c909022a5a56cd1d9e89c8c5461fd1f6a27bb5< 65f4aebb8127708ba668dd938e83b8558abfc5cd affected
58c909022a5a56cd1d9e89c8c5461fd1f6a27bb5< 97bd560b6cc4c26386a53b4881bf03e96f9ba03a affected
58c909022a5a56cd1d9e89c8c5461fd1f6a27bb5< 2b90e7ace79774a3540ce569e000388f8d22c9e0 affected
5.10 affected
< 5.10 unaffected
5.10.235≤ 5.10.* unaffected
… +4 more rows
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I. Basic Information for CVE-2025-21872

Vulnerability Information
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Vulnerability Title
efi: Don't map the entire mokvar table to determine its size
Source: CVE Program / CVE List V5
Vulnerability Description
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.
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于未正确处理mokvar表大小计算，可能导致内存映射失败。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux 58c909022a5a56cd1d9e89c8c5461fd1f6a27bb5 ~ 46c0454ffb78ce9d3355a3cccac86383ea8ddd55 -
Linux Linux 5.10 -

II. Public POCs for CVE-2025-21872

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III. Intelligence Information for CVE-2025-21872

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Patches & Fixes for CVE-2025-21872 (5)

Same Patch Batch · Linux · 2025-03-27 · 124 CVEs total

CVE-2023-53006 9.8 CRITICAL cifs: Fix oops due to uncleared server->smbd_conn in reconnect
CVE-2025-21876 8.8 HIGH iommu/vt-d: Fix suspicious RCU usage
CVE-2025-21890 8.2 HIGH idpf: fix checksums set in idpf_rx_rsc()
CVE-2022-49755 7.8 HIGH usb: gadget: f_fs: Prevent race during ffs_ep0_queue_wait
CVE-2025-21887 7.8 HIGH ovl: fix UAF in ovl_dentry_update_reval by moving dput() in ovl_link_up
CVE-2025-21889 7.8 HIGH perf/core: Add RCU read lock protection to perf_iterate_ctx()
CVE-2023-52930 7.8 HIGH drm/i915: Fix potential bit_17 double-free
CVE-2023-52931 7.8 HIGH drm/i915: Avoid potential vm use-after-free
CVE-2023-52934 7.8 HIGH mm/MADV_COLLAPSE: catch !none !huge !bad pmd lookups
CVE-2023-52935 7.8 HIGH mm/khugepaged: fix ->anon_vma race
CVE-2023-53009 7.8 HIGH drm/amdkfd: Add sync after creating vram bo
CVE-2023-52999 7.8 HIGH net: fix UaF in netns ops registration error path
CVE-2023-52973 7.8 HIGH vc_screen: move load of struct vc_data pointer in vcs_read() to avoid UAF
CVE-2023-52983 7.8 HIGH block, bfq: fix uaf for bfqq in bic_set_bfqq()
CVE-2023-52981 7.8 HIGH drm/i915: Fix request ref counting during error capture & debugfs dump
CVE-2023-52975 7.8 HIGH scsi: iscsi_tcp: Fix UAF during logout when accessing the shost ipaddress
CVE-2023-52974 7.8 HIGH scsi: iscsi_tcp: Fix UAF during login when accessing the shost ipaddress
CVE-2022-49760 7.8 HIGH mm/hugetlb: fix PTE marker handling in hugetlb_change_protection()
CVE-2025-21867 7.8 HIGH bpf, test_run: Fix use-after-free issue in eth_skb_pkt_type()
CVE-2023-52988 7.8 HIGH ALSA: hda/via: Avoid potential array out-of-bound in add_secret_dac_path()

Showing top 20 of 124 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2025-21872

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