---
id: CVE-2026-31533
title: 'net/tls: fix use-after-free in -EBUSY error path of tls_do_encryption'
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'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 3ade391adc584f17b5570fd205de3ad029090368 <
    414fc5e5a5aff776c150f1b86770e0a25a35df3a
  - >-
    Linux >= cd1bbca03f3c1d845ce274c0d0a66de8e5929f72 <
    02f3ecadb23558bbe068e6504118f1b712d4ece0
  - >-
    Linux >= 13eca403876bbea3716e82cdfe6f1e6febb38754 <
    0e43e0a3c94044acc74b8e0927c27972eb5a59e8
  - >-
    Linux >= 8590541473188741055d27b955db0777569438e3 <
    aa9facde6c5005205874c37db3fd25799d741baf
  - >-
    Linux >= 8590541473188741055d27b955db0777569438e3 <
    5d70eb25b41e9b010828cd12818b06a0c3b04412
  - >-
    Linux >= 8590541473188741055d27b955db0777569438e3 <
    2694d408b0e595024e0fc1d64ff9db0358580f74
  - >-
    Linux >= 8590541473188741055d27b955db0777569438e3 <
    a9b8b18364fffce4c451e6f6fd218fa4ab646705
  - Linux ab6397f072e5097f267abf5cb08a8004e6b17694
  - Linux >= 5.15.160 < 5.15.203
  - Linux >= 6.1.84 < 6.1.169
  - Linux >= 6.6.18 < 6.6.135
  - Linux >= 6.7.6 < 6.8
  - Linux 6.8
published: '2026-04-23'
updated: '2026-09-08'
sourceUpdated: '2026-09-08T08:47:40.390Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-31533'
references:
  - url: 'https://git.kernel.org/stable/c/414fc5e5a5aff776c150f1b86770e0a25a35df3a'
  - url: 'https://git.kernel.org/stable/c/02f3ecadb23558bbe068e6504118f1b712d4ece0'
  - url: 'https://git.kernel.org/stable/c/0e43e0a3c94044acc74b8e0927c27972eb5a59e8'
  - url: 'https://git.kernel.org/stable/c/aa9facde6c5005205874c37db3fd25799d741baf'
  - url: 'https://git.kernel.org/stable/c/5d70eb25b41e9b010828cd12818b06a0c3b04412'
  - url: 'https://git.kernel.org/stable/c/2694d408b0e595024e0fc1d64ff9db0358580f74'
  - url: 'https://git.kernel.org/stable/c/a9b8b18364fffce4c451e6f6fd218fa4ab646705'
tags:
  - cve.org
epss: 0.00707
epssPercentile: 0.51417
ingestedAt: '2026-09-08T15:33:26.990Z'
---

## 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 >= 3ade391adc584f17b5570fd205de3ad029090368 < 414fc5e5a5aff776c150f1b86770e0a25a35df3a`
- `Linux >= cd1bbca03f3c1d845ce274c0d0a66de8e5929f72 < 02f3ecadb23558bbe068e6504118f1b712d4ece0`
- `Linux >= 13eca403876bbea3716e82cdfe6f1e6febb38754 < 0e43e0a3c94044acc74b8e0927c27972eb5a59e8`
- `Linux >= 8590541473188741055d27b955db0777569438e3 < aa9facde6c5005205874c37db3fd25799d741baf`
- `Linux >= 8590541473188741055d27b955db0777569438e3 < 5d70eb25b41e9b010828cd12818b06a0c3b04412`
- `Linux >= 8590541473188741055d27b955db0777569438e3 < 2694d408b0e595024e0fc1d64ff9db0358580f74`
- `Linux >= 8590541473188741055d27b955db0777569438e3 < a9b8b18364fffce4c451e6f6fd218fa4ab646705`
- `Linux ab6397f072e5097f267abf5cb08a8004e6b17694`
- `Linux >= 5.15.160 < 5.15.203`
- `Linux >= 6.1.84 < 6.1.169`
- `Linux >= 6.6.18 < 6.6.135`
- `Linux >= 6.7.6 < 6.8`
- `Linux 6.8`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.