CVE-2023-54195
Description
A NULL pointer dereference flaw was found in the Linux kernel's RxRPC/AFS networking stack. When making an AFS call, the call timer can expire before a connection is assigned if the call gets stalled waiting for a connection. This causes a NULL pointer dereference in rxrpc_alloc_txbuf() when attempting to send an ACK.
Statement
This primarily affects AFS filesystem users. Direct exploitation from userspace via AF_RXRPC sockets is prevented as sendmsg() returns EBUSY in the vulnerable state. The issue requires specific timing conditions where connection establishment is delayed while the call timer expires.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.5 | N/A | N/A |
| Attack Vector | Local | N/A | N/A |
| Attack Complexity | Low | N/A | N/A |
| Privileges Required | Low | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | None | N/A | N/A |
| Integrity Impact | None | N/A | N/A |
| Availability Impact | High | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Integrity,Other
Technical Impact: Alter Execution Logic; Unexpected State
The main problem is that -- if a lock is overcome -- data could be altered in a bad state.
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