Use After Free Affecting kernel-obs-build package, versions <5.3.18-150200.24.183.1


Severity

Recommended
0.0
medium
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.04% (15th percentile)

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  • Snyk IDSNYK-SLES152-KERNELOBSBUILD-6482142
  • published23 Mar 2024
  • disclosed18 Mar 2024

Introduced: 18 Mar 2024

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

How to fix?

Upgrade SLES:15.2 kernel-obs-build to version 5.3.18-150200.24.183.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-obs-build package and not the kernel-obs-build package as distributed by SLES. See How to fix? for SLES:15.2 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