CVE-2026-98698

In the Linux kernel, the following vulnerability has been resolved:

wifi: mac80211: handle empty FILS association request payload

fils encrypt assoc req() accepts a (Re)Association Request frame whose last element is the FILS Session element. crypt len is then zero and aes siv encrypt() is called with an empty plaintext.

kmemdup() returns ZERO SIZE PTR for a zero-length allocation, so the unconditional sg init one() puts an invalid page into the scatterlist. With CONFIG DEBUG SG this triggers a kernel BUG in sg set buf(); without the debug check the bogus page is handed to the crypto backend.

AES-SIV is defined for empty plaintext and the S2V result is then the complete output, so handle this case before the CTR step, which has nothing to encrypt.