CVE-2025-39817
Vulnerability Scoring
Analysis In Progress
CVE-2025-39817 Vulnerability Analysis & Exploit Details
CVE-2025-39817
Attack Complexity Details
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Attack Complexity:
Attack Complexity Analysis In Progress
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Attack Vector:
Attack Vector Under Analysis
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Privileges Required:
None
No authentication is required for exploitation.
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Scope:
Impact is confined to the initially vulnerable component.
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User Interaction:
None
No user interaction is necessary for exploitation.
CVE-2025-39817 Details
Status: Awaiting Analysis
Last updated: 🕕 03 Nov 2025, 18:16 UTC
Originally published on: 🕐 16 Sep 2025, 13:15 UTC
Time between publication and last update: 48 days
CVSS Release:
CVE-2025-39817 Vulnerability Summary
CVE-2025-39817: In the Linux kernel, the following vulnerability has been resolved: efivarfs: Fix slab-out-of-bounds in efivarfs_d_compare Observed on kernel 6.6 (present on master as well): BUG: KASAN: slab-out-of-bounds in memcmp+0x98/0xd0 Call trace: kasan_check_range+0xe8/0x190 __asan_loadN+0x1c/0x28 memcmp+0x98/0xd0 efivarfs_d_compare+0x68/0xd8 __d_lookup_rcu_op_compare+0x178/0x218 __d_lookup_rcu+0x1f8/0x228 d_alloc_parallel+0x150/0x648 lookup_open.isra.0+0x5f0/0x8d0 open_last_lookups+0x264/0x828 path_openat+0x130/0x3f8 do_filp_open+0x114/0x248 do_sys_openat2+0x340/0x3c0 __arm64_sys_openat+0x120/0x1a0 If dentry->d_name.len < EFI_VARIABLE_GUID_LEN , 'guid' can become negative, leadings to oob. The issue can be triggered by parallel lookups using invalid filename: T1 T2 lookup_open ->lookup simple_lookup d_add // invalid dentry is added to hash list lookup_open d_alloc_parallel __d_lookup_rcu __d_lookup_rcu_op_compare hlist_bl_for_each_entry_rcu // invalid dentry can be retrieved ->d_compare efivarfs_d_compare // oob Fix it by checking 'guid' before cmp.
Assessing the Risk of CVE-2025-39817
Access Complexity Graph
The exploitability of CVE-2025-39817 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).
Exploitability Analysis for CVE-2025-39817
No exploitability data is available for CVE-2025-39817.
Understanding AC and PR
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.
CVSS Score Breakdown Chart
Above is the CVSS Sub-score Breakdown for CVE-2025-39817, 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.
CIA Impact Analysis
Below is the Impact Analysis for CVE-2025-39817, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.
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Confidentiality:
None
CVE-2025-39817 does not compromise confidentiality.
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Integrity:
None
CVE-2025-39817 does not impact data integrity.
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Availability:
None
CVE-2025-39817 does not affect system availability.
CVE-2025-39817 References
External References
- https://git.kernel.org/stable/c/0f63fbabeaaaaaaf5b742a2f4c1b4590d50bf1f6
- https://git.kernel.org/stable/c/568e7761279b99c6daa3002290fd6d8047ddb6d2
- https://git.kernel.org/stable/c/71581a82f38e5a4d807d71fc1bb59aead80ccf95
- https://git.kernel.org/stable/c/794399019301944fd6d2e0d7a51b3327e26c410e
- https://git.kernel.org/stable/c/925599eba46045930b850a98ae594d2e3028ac40
- https://git.kernel.org/stable/c/a6358f8cf64850f3f27857b8ed8c1b08cfc4685c
- https://git.kernel.org/stable/c/c2925cd6207079c3f4d040d082515db78d63afbf
- https://git.kernel.org/stable/c/d7f5e35e70507d10cbaff5f9e194ed54c4ee14f7
- https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html
- https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html
CWE Common Weakness Enumeration
Unknown
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