Vulnerability in multi-threaded xz decoder

Advisory ID CVE Number Date discovered Severity Advisory revision
STORM-2025-010 CVE-2025-31115 07/03/2025 low v1

Vulnerability details

A heap use-after-free vulnerability in the XZ decoder used by SNS appliances may be triggered by a specially crafted file, potentially causing a crash or arbitrary code execution.

Impacted products

ProductsSeverityDetail
Stormshield Network Security low SNS is impacted.

Revisions

Version Date Description
v1 01/06/2026 Initial release


Stormshield Network Security

CVSS v3.1 Overall Score: 3.5      

Analysis

Impacted version

Stormshield Network Security (SNS) appliances embed the XZ compression library for file decompression. A worker thread could free its input buffer after decoding, while the main thread might still be writing to it. This leads to a use-after-free condition on heap memory.

An attacker may use specifically crafted .xz file to cause multi-threaded xz decoder to crash, or potentially run arbitrary code under the credential the decoder was executed.

 
  • SNS 5.0.0 to 5.0.3

Workaround solution

Solution

There is no workaround solution.

The following update will fix this vulnerability:

  • SNS 5.0.4


Attack Vector Attack Complexity Privileges Required User Interaction Scope Confidentiality Impact Integrity Impact Availability impact
Local High High None Unchanged None None High
CVSS Base score: 4.1 CVSS Vector: (AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H)
Exploit Code Maturity Remediation Level Report Confidence
Unproven that exploit exists Official fix Reasonable
CVSS Temporal score: 3.5 CVSS Vector: (AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:R)
Confidentiality Requirement (CR) Integrity Requirement (IR) Availability Requirement (AR)
Medium Medium Medium
CVSS Environmental score: 3.5 CVSS Vector: (AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:R/CR:M/IR:M/AR:M/MAV:X/MAC:X/MPR:X/MUI:X/MS:X/MC:X/MI:X/MA:X)