Evidence-led vulnerability intelligence · 2026-11-02 21:47 IST

CVE-2026-99225

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

UNRATED · N/ALinux

Executive briefing

The source record describes: 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 The practical risk depends on whether an affected product/version is present, reachable and configured in an exploitable way. Review the affected-product evidence and linked vendor advisories before assigning exposure status.

Assessment: Potential exposure only — validate the installed product, exact version, configuration and vendor applicability before treating an asset as confirmed vulnerable.

Evidence confidence: Limited Evidence-derived, not an exploitability verdict

Severity & attack characteristics

N/A / 10 ·

CVSS vector:

No CVSS vector is currently available in the source record.

Technical explanation & impact

The technical mechanism is not expanded beyond the source description unless a referenced advisory supplies additional evidence. Read the linked vendor/CERT advisories for root-cause detail.

Potential impact must be interpreted from the published CVSS impact metrics and the affected component. A CVSS impact score is not proof that a particular asset is exploitable.

Affected products and versions

NVD has not supplied machine-readable vulnerable CPE product/version entries for this CVE. This is an information gap, not proof that no products are affected. Check the vendor advisory references below.

Remediation & validation

  1. Identify exposure by comparing the affected product and version ranges with your asset inventory, SBOM and externally exposed services.
  2. Review the linked vendor security advisory or patch notes. Upgrade to a vendor-confirmed fixed release; do not infer a fixed version from the CVE description.
  3. Until patched, consider restricting network access or disabling the affected feature where operationally safe. These are temporary controls, not a substitute for a vendor fix.
  4. Validate the remediation with a version check and vulnerability rescan, then retain change evidence.

No fixed version is displayed unless it is explicitly established by a vendor advisory. Follow the vendor's release notes for exact product and branch applicability.

Vendor advisories, patches & exploit references

Information gaps & confidence notes

These gaps indicate missing source data. CVE Watch does not fill them with guessed product, exploit or patch details.

Last enrichment: 2026-11-03T20:31:44+00:00 · Source last modified: 2026-11-03T20:18:28.023

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