7.8

CVE-2021-47013

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.
Data is provided by the National Vulnerability Database (NVD)
Linux ≫ Linux Kernel Version >= 4.9 < 4.9.269
Linux ≫ Linux Kernel Version >= 4.10 < 4.14.233
Linux ≫ Linux Kernel Version >= 4.15 < 4.19.191
Linux ≫ Linux Kernel Version >= 4.20 < 5.4.119
Linux ≫ Linux Kernel Version >= 5.5 < 5.10.37
Linux ≫ Linux Kernel Version >= 5.11 < 5.11.21
Linux ≫ Linux Kernel Version >= 5.12 < 5.12.4
Zu dieser CVE wurde keine CISA KEV oder CERT.AT-Warnung gefunden.
EPSS Metriken
Type Source Score Percentile
EPSS FIRST.org 0.01% 0.012
CVSS Metriken
Source Base Score Exploit Score Impact Score Vector string
nvd@nist.gov 7.8 1.8 5.9
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE-416 Use After Free

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.