CVE intelligence and bounded remediation

CVE-2025-21705 — Linux Linux Kernel security vulnerability

Medium CVSS 5.5

In the Linux kernel, the following vulnerability has been resolved: mptcp: handle fastopen disconnect correctly Syzbot was able to trigger a data stream corruption: WARNING: CPU: 0 PID: 9846 at net/mptcp/protocol.c:1024 __mptcp_clean_una+0xddb/0xff0 net/mptcp/protocol.c:1024 Modules linked in: CPU: 0 UID: 0 PID: 9846 Comm: syz-executor351 Not tainted 6.13.0-rc2-syzkaller-00059-g00a5acdbf398 #0 Hardware name: Google Compute Engine/Google Compute Engine, BIOS Google 11/25/2024 RIP: 0010:__mptcp_clean_una+0xddb/0xff0 net/mptcp/protocol.c:1024 Code: fa ff ff 48 8b 4c 24 18 80 e1 07 fe c1 38 c1 0f 8c 8e fa ff ff 48 8b 7c 24 18 e8 e0 db 54 f6 e9 7f fa ff ff e8 e6 80 ee f5 90 <0f> 0b 90 4c 8b 6c 24 40 4d 89 f4 e9 04 f5 ff ff 44 89 f1 80 e1 07 RSP: 0018:ffffc9000c0cf400 EFLAGS: 00010293 RAX: ffffffff8bb0dd5a RBX: ffff888033f5d230 RCX: ffff888059ce8000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc9000c0cf518 R08: ffffffff8bb0d1dd R09: 1ffff110170c8928 R10: dffffc0000000000 R11: ffffed10170c8929 R12: 0000000000000000 R13: ffff888033f5d220 R14: dffffc0000000000 R15: ffff8880592b8000 FS: 00007f6e866496c0(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS…

Severity
Medium
CVSS
5.5 (3.1)
Published
2025-02-27
CISA KEV
Not currently listed
Ecosystem
linux/kernel

Affected products

  • linux / linux_kernel
  • linux / linux_kernel / 6.4

Showing 2 representative product identities from 6 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

General vulnerability remediation

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Confirm the affected component, deployment paths, reachable interfaces, and enabled features from inventories and configuration, without probing production destructively.
  • Compare the advisory's affected conditions with the repository lockfiles, build manifests, artifacts, and runtime inventory.
  • Identify data sensitivity, trust boundaries, and privilege level for every confirmed affected deployment.

Remediate safely

  • Apply a vendor-supported fix or remove the affected component or feature; record the selected change and its source in the repository.
  • Update direct and transitive dependency locks, generated artifacts, deployment manifests, and asset inventories together.
  • Add a regression test for the documented unsafe condition using inert inputs and preserve rollback instructions.

Authoritative sources

Complete CVE record and remediation plan

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