CVE-2024-41066: ibmvnic: Add tx check to prevent skb leak

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-07-29 · updated 2026-08-04
Weakness: CWE-401

Description

In the Linux kernel, the following vulnerability has been resolved: ibmvnic: Add tx check to prevent skb leak Below is a summary of how the driver stores a reference to an skb during transmit: tx_buff[free_map[consumer_index]]->skb = new_skb; free_map[consumer_index] = IBMVNIC_INVALID_MAP; consumer_index ++; Where variable data looks like this: free_map == [4, IBMVNIC_INVALID_MAP, IBMVNIC_INVALID_MAP, 0, 3] consumer_index^ tx_buff == [skb=null, skb=<ptr>, skb=<ptr>, skb=null, skb=null] The driver has checks to ensure that free_map[consumer_index] pointed to a valid index but there was no check to ensure that this index pointed to an unused/null skb address. So, if, by some chance, our free_map and tx_buff lists become out of sync then we were previously risking an skb memory leak. This could then cause tcp congestion control to stop sending packets, eventually leading to ETIMEDOUT. Therefore, add a conditional to ensure that the skb address is null. If not then warn the user (because this is still a bug that should be patched) and free the old pointer to prevent memleak/tcp problems.

Affected products

Linux kernel: before 6.1.101; from 6.2 before 6.6.42; from 6.7 before 6.9.11; 6.10-rc1, 6.10-rc2, 6.10-rc3, 6.10-rc4, 6.10-rc5 — fixed in 6.1.101, 6.6.42, 6.9.11

How to fix

Upgrade to a fixed version: Linux kernel 6.1.101, 6.6.42, 6.9.11. Check the vendor advisory for mitigations.

References

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