# CVE-2025-68787: netrom: Fix memory leak in nr_sendmsg()

> A memory leak in the Linux kernel's netrom module allows local attackers to exhaust system memory, causing denial of service.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 13 Jan 2026
- **Updated:** 15 Oct 2026
- **Also known as:** AZL-74390, BELL-CVE-2025-68787, DEBIAN-CVE-2025-68787, GHSA-6prc-rrx9-j93r, ROOT-OS-DEBIAN-11-CVE-2025-68787, ROOT-OS-DEBIAN-12-CVE-2025-68787, ROOT-OS-DEBIAN-13-CVE-2025-68787, ROOT-OS-UBUNTU-2204-CVE-2025-68787, ROOT-OS-UBUNTU-2404-CVE-2025-68787, UBUNTU-CVE-2025-68787

## What is CVE-2025-68787?

CVE-2025-68787 is a memory corruption vulnerability in Linux, published on 13 Jan 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official 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

## Which versions are affected by CVE-2025-68787?


## How do I fix CVE-2025-68787?

Apply the vendor's patch.

## Is CVE-2025-68787 being exploited?

There is no known exploitation of CVE-2025-68787 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-68787 and fix it if it is affected.

What it is: CVE-2025-68787 is a memory corruption vulnerability in Linux, published on 13 Jan 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-68787 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-68787/ (Markdown: https://insights.sbomify.com/CVE-2025-68787/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-68787
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-68787
- OSV: https://osv.dev/vulnerability/CVE-2025-68787

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-68787/
Summaries are generated and may contain mistakes; the official description above is the record.