Description
In the Linux kernel, the following vulnerability has been resolved:
mptcp: fix sk_forward_memory corruption on retransmission
MPTCP sk_forward_memory handling is a bit special, as such field
is protected by the msk socket spin_lock, instead of the plain
socket lock.
Currently we have a code path updating such field without handling
the relevant lock:
__mptcp_retrans() -> __mptcp_clean_una_wakeup()
Several helpers in __mptcp_clean_una_wakeup() will update
sk_forward_alloc, possibly causing such field corruption, as reported
by Matthieu.
Address the issue providing and using a new variant of blamed function
which explicitly acquires the msk spin lock.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Linux | Linux | 5.11.4 – < 5.12, 5.12 | 5.12 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 22.04 LTS | linux-riscv +20 | No fix yet | — |
| Ubuntu 20.04 LTS | linux-gke +26 | No fix yet | — |
| Ubuntu 18.04 LTS | linux-gcp +14 | No fix yet | — |
| Ubuntu 16.04 LTS | linux-hwe-edge | No fix yet | — |
Advisories 1
- WID-SEC-2024-0652 Linux Kernel: Mehrere Schwachstellen ermöglichen Denial of Service BSI CERT-Bund (WID) · Aug 13, 2026