---
id: CVE-2025-37756
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net: tls: explicitly disallow disconnect

  syzbot discovered that it can disconnect a TLS socket and then
  run into all sort of unexpected corner cases
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net: tls: explicitly disallow disconnect

  syzbot discovered that it can disconnect a TLS socket and then
  run into all sort of unexpected corner cases. I have a vague
  re…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-20
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 4.13, < 5.10.237'
  - 'linux_kernel >= 5.11, < 5.15.181'
  - 'linux_kernel >= 5.16, < 6.1.135'
  - 'linux_kernel >= 6.2, < 6.6.88'
  - 'linux_kernel >= 6.7, < 6.12.24'
  - 'linux_kernel >= 6.13, < 6.13.12'
  - 'linux_kernel >= 6.14, < 6.14.3'
  - linux_kernel = 6.15
  - debian_linux = 11.0
patched:
  - linux_kernel 6.14.3
published: '2025-05-01'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T22:18:17.173'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-37756'
references:
  - url: 'https://git.kernel.org/stable/c/2bcad8fefcecdd5f005d8c550b25d703c063c34a'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/5071a1e606b30c0c11278d3c6620cd6a24724cf6'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/7bdcf5bc35ae59fc4a0fa23276e84b4d1534a3cf'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/8513411ec321942bd3cfed53d5bb700665c67d86'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/9fcbca0f801580cbb583e9cb274e2c7fbe766ca6'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/ac91c6125468be720eafde9c973994cb45b61d44'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/c665bef891e8972e1d3ce5bbc0d42a373346a2c3'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/f3ce4d3f874ab7919edca364c147ac735f9f1d04'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'http://www.openwall.com/lists/oss-security/2026/05/07/1'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-37756.json
  - url: 'https://access.redhat.com/security/cve/CVE-2025-37756'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2363326'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2025-37756'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2025-37756'
  - url: >-
      https://lore.kernel.org/linux-cve-announce/2025050139-CVE-2025-37756-a06e@gregkh/T
tags:
  - nvd
  - csaf
  - vex
  - red-hat
  - cve.org
  - score-dispute
epss: 0.00298
epssPercentile: 0.22304
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-15T21:44:56.970467Z'
scores:
  nvd: 7.8
  vendor: 3.3
  cna: 7.8
ingestedAt: '2026-10-15T22:48:25.477Z'
---

## Overview

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

net: tls: explicitly disallow disconnect

syzbot discovered that it can disconnect a TLS socket and then
run into all sort of unexpected corner cases. I have a vague
recollection of Eric pointing this out to us a long time ago.
Supporting disconnect is really hard, for one thing if offload
is enabled we'd need to wait for all packets to be _acked_.
Disconnect is not commonly used, disallow it.

The immediate problem syzbot run into is the warning in the strp,
but that's just the easiest bug to trigger:

  WARNING: CPU: 0 PID: 5834 at net/tls/tls_strp.c:486 tls_strp_msg_load+0x72e/0xa80 net/tls/tls_strp.c:486
  RIP: 0010:tls_strp_msg_load+0x72e/0xa80 net/tls/tls_strp.c:486
  Call Trace:
   <TASK>
   tls_rx_rec_wait+0x280/0xa60 net/tls/tls_sw.c:1363
   tls_sw_recvmsg+0x85c/0x1c30 net/tls/tls_sw.c:2043
   inet6_recvmsg+0x2c9/0x730 net/ipv6/af_inet6.c:678
   sock_recvmsg_nosec net/socket.c:1023 [inline]
   sock_recvmsg+0x109/0x280 net/socket.c:1045
   __sys_recvfrom+0x202/0x380 net/socket.c:2237

## Affected

- `linux_kernel >= 4.13, < 5.10.237`
- `linux_kernel >= 5.11, < 5.15.181`
- `linux_kernel >= 5.16, < 6.1.135`
- `linux_kernel >= 6.2, < 6.6.88`
- `linux_kernel >= 6.7, < 6.12.24`
- `linux_kernel >= 6.13, < 6.13.12`
- `linux_kernel >= 6.14, < 6.14.3`
- `linux_kernel = 6.15`
- `debian_linux = 11.0`

## Remediation

Upgrade past the affected range:

- `linux_kernel 6.14.3`

## Vendor advisories

- **Red Hat VEX** · Low · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9 · updated 2026-10-16 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-37756.json)