Use After Free Affecting kernel-debug-modules package, versions <0:4.18.0-372.105.1.el8_6


Severity

Recommended
medium

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.04% (5th percentile)

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  • Snyk IDSNYK-RHEL8-KERNELDEBUGMODULES-7159364
  • published29 May 2024
  • disclosed28 Feb 2024

Introduced: 28 Feb 2024

CVE-2021-47013  (opens in a new tab)
CWE-416  (opens in a new tab)

How to fix?

Upgrade RHEL:8 kernel-debug-modules to version 0:4.18.0-372.105.1.el8_6 or higher.
This issue was patched in RHSA-2024:3462.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-debug-modules package and not the kernel-debug-modules package as distributed by RHEL. See How to fix? for RHEL:8 relevant fixed versions and status.

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

net:emac/emac-mac: Fix a use after free in emac_mac_tx_buf_send

In emac_mac_tx_buf_send, it calls emac_tx_fill_tpd(..,skb,..). If some error happens in emac_tx_fill_tpd(), the skb will be freed via dev_kfree_skb(skb) in error branch of emac_tx_fill_tpd(). But the freed skb is still used via skb->len by netdev_sent_queue(,skb->len).

As i observed that emac_tx_fill_tpd() haven't modified the value of skb->len, thus my patch assigns skb->len to 'len' before the possible free and use 'len' instead of skb->len later.

CVSS Scores

version 3.1