---
id: CVE-2026-31533
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net/tls: fix use-after-free in -EBUSY error path of tls_do_encryption

  The -EBUSY handling in tls_do_encryption(), introduced by commit
  859054147318 ("net: tls: handle …
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net/tls: fix use-after-free in -EBUSY error path of tls_do_encryption

  The -EBUSY handling in tls_do_encryption(), introduced by commit
  859054147318 ("net: tls: handle …
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-416
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 5.15.160, < 5.15.203'
  - 'linux_kernel >= 6.1.84, < 6.1.169'
  - 'linux_kernel >= 6.6.18, < 6.6.135'
  - 'linux_kernel >= 6.7.6, < 6.8'
  - 'linux_kernel >= 6.8.1, < 6.12.82'
  - 'linux_kernel >= 6.13, < 6.18.23'
  - 'linux_kernel >= 6.19, < 6.19.13'
  - linux_kernel = 7.0
patched:
  - linux_kernel 6.19.13
published: '2026-04-23'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T02:19:10.650'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-31533'
references:
  - url: 'https://git.kernel.org/stable/c/02f3ecadb23558bbe068e6504118f1b712d4ece0'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/0e43e0a3c94044acc74b8e0927c27972eb5a59e8'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/2694d408b0e595024e0fc1d64ff9db0358580f74'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/414fc5e5a5aff776c150f1b86770e0a25a35df3a'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/5d70eb25b41e9b010828cd12818b06a0c3b04412'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/a9b8b18364fffce4c451e6f6fd218fa4ab646705'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/aa9facde6c5005205874c37db3fd25799d741baf'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-019113.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-082556.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-457936.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
tags:
  - nvd
  - cve.org
epss: 0.00398
epssPercentile: 0.33893
ingestedAt: '2026-09-08T15:33:26.990Z'
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-10-16T15:10:43.493740Z'
---

## Overview

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

net/tls: fix use-after-free in -EBUSY error path of tls_do_encryption

The -EBUSY handling in tls_do_encryption(), introduced by commit
859054147318 ("net: tls: handle backlogging of crypto requests"), has
a use-after-free due to double cleanup of encrypt_pending and the
scatterlist entry.

When crypto_aead_encrypt() returns -EBUSY, the request is enqueued to
the cryptd backlog and the async callback tls_encrypt_done() will be
invoked upon completion. That callback unconditionally restores the
scatterlist entry (sge->offset, sge->length) and decrements
ctx->encrypt_pending. However, if tls_encrypt_async_wait() returns an
error, the synchronous error path in tls_do_encryption() performs the
same cleanup again, double-decrementing encrypt_pending and
double-restoring the scatterlist.

The double-decrement corrupts the encrypt_pending sentinel (initialized
to 1), making tls_encrypt_async_wait() permanently skip the wait for
pending async callbacks. A subsequent sendmsg can then free the
tls_rec via bpf_exec_tx_verdict() while a cryptd callback is still
pending, resulting in a use-after-free when the callback fires on the
freed record.

Fix this by skipping the synchronous cleanup when the -EBUSY async
wait returns an error, since the callback has already handled
encrypt_pending and sge restoration.

## Affected

- `linux_kernel >= 5.15.160, < 5.15.203`
- `linux_kernel >= 6.1.84, < 6.1.169`
- `linux_kernel >= 6.6.18, < 6.6.135`
- `linux_kernel >= 6.7.6, < 6.8`
- `linux_kernel >= 6.8.1, < 6.12.82`
- `linux_kernel >= 6.13, < 6.18.23`
- `linux_kernel >= 6.19, < 6.19.13`
- `linux_kernel = 7.0`

## Remediation

Upgrade past the affected range:

- `linux_kernel 6.19.13`