CVE-2024-39490: ipv6: sr: fix missing sk_buff release in seg6_input_core

Severity: medium (CVSS 6.2 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: 2024-07-10 · updated 2026-06-17
Weakness: CWE-401

Description

In the Linux kernel, the following vulnerability has been resolved: ipv6: sr: fix missing sk_buff release in seg6_input_core The seg6_input() function is responsible for adding the SRH into a packet, delegating the operation to the seg6_input_core(). This function uses the skb_cow_head() to ensure that there is sufficient headroom in the sk_buff for accommodating the link-layer header. In the event that the skb_cow_header() function fails, the seg6_input_core() catches the error but it does not release the sk_buff, which will result in a memory leak. This issue was introduced in commit af3b5158b89d ("ipv6: sr: fix BUG due to headroom too small after SRH push") and persists even after commit 7a3f5b0de364 ("netfilter: add netfilter hooks to SRv6 data plane"), where the entire seg6_input() code was refactored to deal with netfilter hooks. The proposed patch addresses the identified memory leak by requiring the seg6_input_core() function to release the sk_buff in the event that skb_cow_head() fails.

Affected products

Linux kernel: from 4.12 before 5.15.161; from 5.16 before 6.1.93; from 6.2 before 6.6.33; from 6.7 before 6.9.4 — fixed in 5.15.161, 6.1.93, 6.6.33, 6.9.4

How to fix

Upgrade to a fixed version: Linux kernel 5.15.161, 6.1.93, 6.6.33, 6.9.4. Check the vendor advisory for mitigations.

References

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