CVE-2021-47236: net: cdc_eem: fix tx fixup skb leak

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-05-21 · updated 2026-06-17
Weakness: CWE-401

Description

In the Linux kernel, the following vulnerability has been resolved: net: cdc_eem: fix tx fixup skb leak when usbnet transmit a skb, eem fixup it in eem_tx_fixup(), if skb_copy_expand() failed, it return NULL, usbnet_start_xmit() will have no chance to free original skb. fix it by free orginal skb in eem_tx_fixup() first, then check skb clone status, if failed, return NULL to usbnet.

Affected products

Linux kernel: from 2.6.30 before 4.4.274; from 4.5 before 4.9.274; from 4.10 before 4.14.238; from 4.15 before 4.19.196; from 4.20 before 5.4.128; from 5.5 before 5.10.46 — fixed in 4.14.238, 4.19.196, 4.4.274, 4.9.274, 5.10.46, 5.12.13

How to fix

Upgrade to a fixed version: Linux kernel 4.14.238, 4.19.196, 4.4.274, 4.9.274. Check the vendor advisory for mitigations.

References

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