---
id: CVE-2026-98584
title: 'net/sched: fix potential stack infoleak in em_text_dump()'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net/sched: fix potential stack infoleak in em_text_dump()

  em_text_dump() allocates struct tcf_em_text on the stack without zeroing
  it.  strscpy() writes the algorithm …
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= b04202d6065cba5dfd51fb9866400b25573eac67 <
    9923e1c537f91f3530b52d4efce85f3d9c131bf8
  - >-
    Linux >= b04202d6065cba5dfd51fb9866400b25573eac67 <
    0b160417826d22f24fc31a5b9cfae3b14aa70f76
  - >-
    Linux >= b04202d6065cba5dfd51fb9866400b25573eac67 <
    9c572a83037a7dcd653ba3a9cc468c16b857d0c9
  - Linux 6.17
published: '2026-10-18'
updated: '2026-10-18'
sourceUpdated: '2026-10-18T15:18:57.204Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-98584'
references:
  - url: 'https://git.kernel.org/stable/c/9923e1c537f91f3530b52d4efce85f3d9c131bf8'
  - url: 'https://git.kernel.org/stable/c/0b160417826d22f24fc31a5b9cfae3b14aa70f76'
  - url: 'https://git.kernel.org/stable/c/9c572a83037a7dcd653ba3a9cc468c16b857d0c9'
tags:
  - cve.org
ingestedAt: '2026-10-18T15:45:12.253Z'
---

## Overview

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

net/sched: fix potential stack infoleak in em_text_dump()

em_text_dump() allocates struct tcf_em_text on the stack without zeroing
it.  strscpy() writes the algorithm name and a NUL terminator into
conf.algo[], leaving the remaining bytes uninitialised.  nla_put_nohdr()
then copies the full struct to the netlink response.

KMSAN on Linux 7.2-rc6 reports two kernel-infoleak splats from this path,
one triggered via "tc filter show" and one via a raw RTM_GETTFILTER dump:

  BUG: KMSAN: kernel-infoleak in _copy_to_iter+0x1c9/0x2620
    nla_put_nohdr+0x83/0x130
    em_text_dump+0x291/0x550
  Local variable conf created at: em_text_dump+0x5d/0x550
  Bytes 168-179 of 199 are uninitialized

I am not certain whether this constitutes a real security problem in
practice: the test was conducted in a controlled KMSAN environment and
the leaked stack bytes may or may not carry sensitive data on actual
production kernels.  I am reporting it because KMSAN flagged it as a
kernel-infoleak and the fix is straightforward.  I can provide a
userspace reproducer on request.

The original code used strncpy() which zero-pads to the destination size.
Commit b04202d6065c ("net/sched: replace strncpy with strscpy") replaced
it with strscpy(), which does not pad, creating this condition.
Zero-initialising the struct closes it.

## Affected

- `Linux >= b04202d6065cba5dfd51fb9866400b25573eac67 < 9923e1c537f91f3530b52d4efce85f3d9c131bf8`
- `Linux >= b04202d6065cba5dfd51fb9866400b25573eac67 < 0b160417826d22f24fc31a5b9cfae3b14aa70f76`
- `Linux >= b04202d6065cba5dfd51fb9866400b25573eac67 < 9c572a83037a7dcd653ba3a9cc468c16b857d0c9`
- `Linux 6.17`

## Remediation

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