CVE-2021-47593
In the Linux kernel, the following vulnerability has been resolved: mptcp: clear 'kern' flag from fallback sockets The mptcp ULP extension relies on sk->sk_sock_kern being set correctly: It prevents setsockopt(fd, IPPROTO_TCP, TCP_ULP, "mptcp", 6); from…
Does this matter?
Lower severity and a low EPSS score (0.25%). Track it; it rarely justifies an emergency change on its own.
Description
In the Linux kernel, the following vulnerability has been resolved: mptcp: clear 'kern' flag from fallback sockets The mptcp ULP extension relies on sk->sk_sock_kern being set correctly: It prevents setsockopt(fd, IPPROTO_TCP, TCP_ULP, "mptcp", 6); from working for plain tcp sockets (any userspace-exposed socket). But in case of fallback, accept() can return a plain tcp sk. In such case, sk is still tagged as 'kernel' and setsockopt will work. This will crash the kernel, The subflow extension has a NULL ctx->conn mptcp socket: BUG: KASAN: null-ptr-deref in subflow_data_ready+0x181/0x2b0 Call Trace: tcp_data_ready+0xf8/0x370 [..]
- CVSS 3.1
- 5.5 MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 0.25% probability · 16th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-476
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/451f1eded7f56e93aaf52eb547ba97742d9c0e97Patch
- https://git.kernel.org/stable/c/c26ac0ea3a91c210cf90452e625dc441adf3e549Patch
- https://git.kernel.org/stable/c/d6692b3b97bdc165d150f4c1505751a323a80717Patch
- https://git.kernel.org/stable/c/451f1eded7f56e93aaf52eb547ba97742d9c0e97Patch
- https://git.kernel.org/stable/c/c26ac0ea3a91c210cf90452e625dc441adf3e549Patch
- https://git.kernel.org/stable/c/d6692b3b97bdc165d150f4c1505751a323a80717Patch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.