CVE-2024-26752: Debian Linux

Medium severity, CVSS 5.5. EPSS: 0.3% chance of exploitation in the next 30 days.

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

• Debian Debian Linux: version 10.0 only
• Linux Linux Kernel: from 4.19.296, before 4.19.308 (fixed in 4.19.308); from 5.4.258, before 5.4.270 (fixed in 5.4.270); from 5.10.198, before 5.10.211 (fixed in 5.10.211); from 5.15.135, before 5.15.150 (fixed in 5.15.150); from 6.1.57, before 6.1.80 (fixed in 6.1.80); from 6.6, before 6.6.19 (fixed in 6.6.19); …

Published 2024-04-03. Last modified 2026-06-17.