linux-cve-announce - CVE-2025-68787: netrom: Fix memory leak in nr

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Message-ID: <2026011303-CVE-2025-68787-af6d@gregkh>
Date: Tue, 13 Jan 2026 16:29:13 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-68787: netrom: Fix memory leak in nr_sendmsg()

From: Greg Kroah-Hartman <gregkh@...nel.org>

Description
===========

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

netrom: Fix memory leak in nr_sendmsg()

syzbot reported a memory leak [1].

When function sock_alloc_send_skb() return NULL in nr_output(), the
original skb is not freed, which was allocated in nr_sendmsg(). Fix this
by freeing it before return.

[1]
BUG: memory leak
unreferenced object 0xffff888129f35500 (size 240):
  comm "syz.0.17", pid 6119, jiffies 4294944652
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    00 00 00 00 00 00 00 00 00 10 52 28 81 88 ff ff  ..........R(....
  backtrace (crc 1456a3e4):
    kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
    slab_post_alloc_hook mm/slub.c:4983 [inline]
    slab_alloc_node mm/slub.c:5288 [inline]
    kmem_cache_alloc_node_noprof+0x36f/0x5e0 mm/slub.c:5340
    __alloc_skb+0x203/0x240 net/core/skbuff.c:660
    alloc_skb include/linux/skbuff.h:1383 [inline]
    alloc_skb_with_frags+0x69/0x3f0 net/core/skbuff.c:6671
    sock_alloc_send_pskb+0x379/0x3e0 net/core/sock.c:2965
    sock_alloc_send_skb include/net/sock.h:1859 [inline]
    nr_sendmsg+0x287/0x450 net/netrom/af_netrom.c:1105
    sock_sendmsg_nosec net/socket.c:727 [inline]
    __sock_sendmsg net/socket.c:742 [inline]
    sock_write_iter+0x293/0x2a0 net/socket.c:1195
    new_sync_write fs/read_write.c:593 [inline]
    vfs_write+0x45d/0x710 fs/read_write.c:686
    ksys_write+0x143/0x170 fs/read_write.c:738
    do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
    do_syscall_64+0xa4/0xfa0 arch/x86/entry/syscall_64.c:94
    entry_SYSCALL_64_after_hwframe+0x77/0x7f

The Linux kernel CVE team has assigned CVE-2025-68787 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 6.1.160 with commit 73839497bbde5cd4fd02bbd9c8bc2640780ae65d
	Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 6.6.120 with commit 156a0f6341dce634a825db49ca20b48b1ae9bcc1
	Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 6.12.64 with commit 8d1ccba4b171cd504ecfa47349cb9864fc9d687c
	Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 6.18.3 with commit 51f5fbc1681bdcffcc7d18bf3dfdb2b1278d3977
	Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 6.19-rc2 with commit 613d12dd794e078be8ff3cf6b62a6b9acf7f4619

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2025-68787
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	net/netrom/nr_out.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/73839497bbde5cd4fd02bbd9c8bc2640780ae65d
	https://git.kernel.org/stable/c/156a0f6341dce634a825db49ca20b48b1ae9bcc1
	https://git.kernel.org/stable/c/8d1ccba4b171cd504ecfa47349cb9864fc9d687c
	https://git.kernel.org/stable/c/51f5fbc1681bdcffcc7d18bf3dfdb2b1278d3977
	https://git.kernel.org/stable/c/613d12dd794e078be8ff3cf6b62a6b9acf7f4619