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Unrated severityNVD Advisory· Published Apr 3, 2024· Updated May 4, 2025

l2tp: pass correct message length to ip6_append_data

CVE-2024-26752

Description

In the Linux kernel, the following vulnerability has been resolved:

l2tp: pass correct message length to ip6_append_data

l2tp_ip6_sendmsg needs to avoid accounting for the transport header twice when splicing more data into an already partially-occupied skbuff.

To manage this, we check whether the skbuff contains data using skb_queue_empty when deciding how much data to append using ip6_append_data.

However, the code which performed the calculation was incorrect:

ulen = len + skb_queue_empty(&sk->sk_write_queue) ? transhdrlen : 0;

...due to C operator precedence, this ends up setting ulen to transhdrlen for messages with a non-zero length, which results in corrupted packets on the wire.

Add parentheses to correct the calculation in line with the original intent.

Affected products

24

Patches

0

No patches discovered yet.

Vulnerability mechanics

AI mechanics synthesis has not run for this CVE yet.

References

8

News mentions

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