CVE-2026-99225
UnknownSummary
A vulnerability exists in the Linux kernel's search_process_keyrings_rcu() function, which validates the authorization payload and saved credentials. Due to a race condition between a request-key helper's descendant and the requester, request_key_auth_revoke() can clear the payload pointer, leading to a NULL dereference and kernel oops.
Risk Assessment
The flaw can be exploited by a local user or helper descendant to trigger a kernel oops and cause a denial of service (DoS). In multi-tenant environments, this may destabilize the system.
Recommendation
Update the Linux kernel to a version containing the fix that loads the payload via dereference_key_rcu() and requires a non-NULL result before validating the authorization key. If updating is not possible, restrict request-key helper execution to trusted processes.
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- CVE-2026-58828High
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- CVE-2026-58827High
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- CVE-2026-99242Unknown
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- CVE-2026-99241Unknown
In the Linux kernel, a missing lock in ntfs_filemap_page_mkwrite() was fixed; it called iomap_page_mkwrite() without holding mapping->invalidate_lock. A concurrent truncate or fallocate could be invalidating pagecache and rewriting the runlist while the write fault mapped blocks and dirtied the folio.
- CVE-2026-99240Unknown
In the Linux kernel, the DAMON subsystem (mm/damon/core) has a division-by-zero bug when a DAMOS quota goal has a target_value of zero. The fix moves handling of this corner case to the core layer by adding validation in damos_commit_quota_goal(), which now returns an error for zero target values.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: keys: Check the authorization payload in process keyring searches An authorization payload and its saved credentials must remain valid while search_process_keyrings_rcu() searches the requestor's keyrings. The function validates the authorization key, then separately loads payload.data[0] and unconditionally reads rka->cred. Validation does not prevent request_key_auth_revoke() from clearing the payload. A request-key helper can assume authority and fork a descendant that inherits the authorization key. If the descendant misses in its own keyrings, it falls back to the saved requestor credentials. Successful target instantiation invalidates the authorization key without clearing the payload. After the helper exits, UMH_WAIT_PROC returns to the requester, which calls complete_request_key() and revokes that key. With the descendant paused after validation, the paths can interleave as follows: 1. The descendant enters search_process_keyrings_rcu() under RCU and key_validate() succeeds. 2. The helper instantiates the target, invalidates the authorization key, and exits. 3. The requester resumes from UMH_WAIT_PROC, calls complete_request_key(), and revokes the authorization key. request_key_auth_revoke() sets its payload pointer to NULL. 4. The descendant loads NULL and dereferences rka->cred. This NULL dereference can oops the kernel. RCU delays payload disposal but does not prevent the pointer from being cleared. Load the payload with dereference_key_rcu() and require a non-NULL result before validating the authorization key and searching its saved credentials. A non-NULL payload and its credentials remain alive for the caller's RCU read-side section; a cleared payload skips the fallback search and follows the existing error selection. KASAN report as below: Oops: general protection fault, probably for non-canonical address 0xdffffc0000000005: 0000 [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f] RIP: 0010:search_process_keyrings_rcu+0x32b/0x790
Vulnerability data from NVD (NIST) · CISA KEV · EPSS