AZL-74712

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Import Source

https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-74712.json

JSON Data

https://api.test.osv.dev/v1/vulns/AZL-74712

Upstream

CVE-2025-39817

Published

2025-09-16T13:15:57Z

Modified

2026-04-01T05:22:45Z

Summary

CVE-2025-39817 affecting package kernel for versions less than 5.15.200.1-1

Details

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.

References

https://nvd.nist.gov/vuln/detail/CVE-2025-39817

Affected packages

Azure Linux:2 / kernel

Package

Name: kernel
Purl: pkg:rpm/azure-linux/kernel

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0 Unknown introduced version / All previous versions are affected

Fixed

5.15.200.1-1

Database specific

source

"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-74712.json"