HIGH Introduced in 6.15
krb5 DerivedKey Leak
CVE-2026-80924
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
KernelScan AI4.7MEDIUM
01Description
In the Linux kernel, the following vulnerability has been resolved: crypto: krb5 - use kfree_sensitive() for derived key buffers crypto_krb5_prepare_encryption() and crypto_krb5_prepare_checksum() free the buffer holding the freshly derived keys with plain kfree(), leaving the key material behind in the freed slab object.
02KernelScan AI Analysis
Risk summary
The Kerberos crypto subsystem frees buffers containing freshly derived encryption and checksum keys without zeroing them, leaving sensitive key material in freed kernel slab objects. A local attacker who can reclaim that slab and read its contents could recover cryptographic keys used to protect NFS or AFS traffic. Products using Kerberos-authenticated network filesystems on systems with local untrusted code are most at risk.
Vulnerability analysis
When the kernel's Kerberos crypto core derives encryption and checksum keys, it stores them in a temporary buffer and then frees that buffer with a plain memory deallocator that does not zero the contents. This leaves the raw key material sitting in a freed slab object, where a local process that subsequently allocates the same slab could read it. The fix replaces the plain deallocator with one that zeroes the buffer before freeing it, ensuring no key material survives in freed memory. The vulnerable path is reached when the kernel sets up Kerberos authentication for network filesystems such as NFS or AFS, and exploitation requires local access to the system to reclaim and inspect the freed slab.
03Fix Versions
| Branch | Introduced | Fixed in | Patch commit |
|---|---|---|---|
| 6.18 | 6.15 | 6.18.49 | 731a5b6fb4c1 |
| 7.1 | 6.15 | 7.1.13 | 91b96dc9cc25 |
| 7.2 | 6.15 | 7.2.3 | a1bf79365794 |
| mainline | 6.15 | 7.3-rc1 | f7d53dd3f267 |