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Out-of-bounds Read The advisory has been revoked - it doesn't affect any version of package bpftool  (opens in a new tab)

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  • Snyk IDSNYK-RHEL7-BPFTOOL-12864491
  • published17 Sept 2025
  • disclosed16 Sept 2025
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Introduced: 16 Sep 2025

CVE-2025-39817  (opens in a new tab)
CWE-125  (opens in a new tab)

Amendment

The Red Hat security team deemed this advisory irrelevant for RHEL:7.

NVD Description

Note: Versions mentioned in the description apply only to the upstream bpftool package and not the bpftool package as distributed by RHEL.

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
             -&gt;d_compare
              efivarfs_d_compare
              // oob

Fix it by checking 'guid' before cmp.

References