Use After Free Affecting kernel-default-base package, versions <5.14.21-150500.55.73.1.150500.6.33.8


Severity

Recommended
0.0
medium
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.01% (2nd percentile)

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  • Snyk IDSNYK-SLES155-KERNELDEFAULTBASE-7705781
  • published17 Aug 2024
  • disclosed16 Aug 2024

Introduced: 16 Aug 2024

CVE-2024-40900  (opens in a new tab)
CWE-416  (opens in a new tab)

How to fix?

Upgrade SLES:15.5 kernel-default-base to version 5.14.21-150500.55.73.1.150500.6.33.8 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-default-base package and not the kernel-default-base package as distributed by SLES. See How to fix? for SLES:15.5 relevant fixed versions and status.

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

cachefiles: remove requests from xarray during flushing requests

Even with CACHEFILES_DEAD set, we can still read the requests, so in the following concurrency the request may be used after it has been freed:

 mount  |   daemon_thread1    |    daemon_thread2

cachefiles_ondemand_init_object cachefiles_ondemand_send_req REQ_A = kzalloc(sizeof(*req) + data_len) wait_for_completion(&REQ_A->done) cachefiles_daemon_read cachefiles_ondemand_daemon_read // close dev fd cachefiles_flush_reqs complete(&REQ_A->done) kfree(REQ_A) xa_lock(&cache->reqs); cachefiles_ondemand_select_req req->msg.opcode != CACHEFILES_OP_READ // req use-after-free !!! xa_unlock(&cache->reqs); xa_destroy(&cache->reqs)

Hence remove requests from cache->reqs when flushing them to avoid accessing freed requests.

CVSS Base Scores

version 3.1