CVE-2026-68147: In the Linux kernel, the following vulnerability has been resolved: fscrypt: Avoid dynamic allocation in fscrypt_get_devices() When a blk_crypto_key...

Description

In the Linux kernel, the following vulnerability has been resolved: fscrypt: Avoid dynamic allocation in fscrypt_get_devices() When a blk_crypto_key starts being used or is evicted, fs/crypto/ calls fscrypt_get_devices() to get the filesystem's list of block devices, then iterates over them and calls blk_crypto_config_supported(), blk_crypto_start_using_key(), or blk_crypto_evict_key() on each one. Currently, the block device pointers are placed in a dynamically allocated array. This dynamic allocation is problematic because: - It can fail, especially at the fscrypt_destroy_inline_crypt_key() call site when it's invoked for inode eviction under direct reclaim. - fscrypt_destroy_inline_crypt_key() doesn't handle the failure. It just zeroizes and frees the blk_crypto_key without calling blk_crypto_evict_key(). That causes a use-after-free. For now, let's fix this in the straightforward and easily-backportable way by switching to an on-stack array. Currently the fscrypt multi-device functionality is used only by f2fs, which has a hardcoded limit of 8 block devices. An on-stack array works fine for that. (Of course, this solution won't scale up to large number of block devices. For that we'd need a different solution, like moving the block device iteration into the filesystem. Or in the case of btrfs, which will only support blk-crypto-fallback, we should make it just call blk-crypto-fallback directly, so the block devices won't be needed.)

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
Linux	Linux	>= 22e9947a4b2ba255888541bd0111cf00b9b16586, < 4462ac3d90e897dda52ce4b6af2d526ddae835a8; >= 22e9947a4b2ba255888541bd0111cf00b9b16586, < 97a688563be71ec6fefc071aff69a66c69dbe244; >= 22e9947a4b2ba255888541bd0111cf00b9b16586, < 81ea8e8221853950c47dac7164f27c63a96f8f86; >= 22e9947a4b2ba255888541bd0111cf00b9b16586, < bc2d630296e0e049210ec05ff08459a6893ae749; >= 22e9947a4b2ba255888541bd0111cf00b9b16586, < 6fe4e4b8259e1330945b5f3c9476e08473b8e0e8
Linux	Linux	6.1

References

Timeline

Published: Aug 10, 2026
Last Modified: Aug 10, 2026
Status: Received

Frequently Asked Questions

What is CVE-2026-68147?

In the Linux kernel, the following vulnerability has been resolved: fscrypt: Avoid dynamic allocation in fscrypt_get_devices() When a blk_crypto_key starts being used or is evicted, fs/crypto/ calls fscrypt_get_devices() to get the filesystem's list of block devices, then iterates over them and calls blk_crypto_config_supported(), blk_crypto_start_using_key(), or blk_crypto_evict_key() on each one. Currently, the block device pointers are placed in a dynamically allocated array. This dynamic allocation is problematic because: - It can fail, especially at the fscrypt_destroy_inline_crypt_key() call site when it's invoked for inode eviction under direct reclaim. - fscrypt_destroy_inline_crypt_key() doesn't handle the failure. It just zeroizes and frees the blk_crypto_key without calling blk_crypto_evict_key(). That causes a use-after-free. For now, let's fix this in the straightforward and easily-backportable way by switching to an on-stack array. Currently the fscrypt multi-device functionality is used only by f2fs, which has a hardcoded limit of 8 block devices. An on-stack array works fine for that. (Of course, this solution won't scale up to large number of block devices. For that we'd need a different solution, like moving the block device iteration into the filesystem. Or in the case of btrfs, which will only support blk-crypto-fallback, we should make it just call blk-crypto-fallback directly, so the block devices won't be needed.)

How severe is CVE-2026-68147?

Severity scoring for CVE-2026-68147 is pending analysis.

How do I fix CVE-2026-68147?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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