Security assessments indicate that CVE-2025-21740 presents a notable risk, potentially requiring prompt mitigation.
Status: Analyzed
Last updated: 🕛 06 Mar 2025, 12:21 UTC
Originally published on: 🕒 27 Feb 2025, 03:15 UTC
Time between publication and last update: 7 days
CVSS Release: version 3
nvd@nist.gov
Primary
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CVE-2025-21740: In the Linux kernel, the following vulnerability has been resolved: KVM: x86/mmu: Ensure NX huge page recovery thread is alive before waking When waking a VM's NX huge page recovery thread, ensure the thread is actually alive before trying to wake it. Now that the thread is spawned on-demand during KVM_RUN, a VM without a recovery thread is reachable via the related module params. BUG: kernel NULL pointer dereference, address: 0000000000000040 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:vhost_task_wake+0x5/0x10 Call Trace: <TASK> set_nx_huge_pages+0xcc/0x1e0 [kvm] param_attr_store+0x8a/0xd0 module_attr_store+0x1a/0x30 kernfs_fop_write_iter+0x12f/0x1e0 vfs_write+0x233/0x3e0 ksys_write+0x60/0xd0 do_syscall_64+0x5b/0x160 entry_SYSCALL_64_after_hwframe+0x4b/0x53 RIP: 0033:0x7f3b52710104 </TASK> Modules linked in: kvm_intel kvm CR2: 0000000000000040
The exploitability of CVE-2025-21740 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).
CVE-2025-21740 presents an accessible attack vector with minimal effort required. Restricting access controls and implementing security updates are critical to reducing exploitation risks.
A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.
Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.
Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.
Above is the CVSS Sub-score Breakdown for CVE-2025-21740, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.
Below is the Impact Analysis for CVE-2025-21740, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.
The EPSS score estimates the probability that this vulnerability will be exploited in the near future.
EPSS Score: 0.042% (probability of exploit)
EPSS Percentile: 5.02%
(lower percentile = lower relative risk)
This vulnerability is less risky than approximately 94.98% of others.
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