// For flags

CVE-2023-3776

Use-after-free in Linux kernel's net/sched: cls_fw component

Severity Score

7.8
*CVSS v3.1

Exploit Likelihood

< 1%
*EPSS

Affected Versions

5
*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

Track*
*SSVC
Descriptions

A use-after-free vulnerability in the Linux kernel's net/sched: cls_fw component can be exploited to achieve local privilege escalation. If tcf_change_indev() fails, fw_set_parms() will immediately return an error after incrementing or decrementing the reference counter in tcf_bind_filter(). If an attacker can control the reference counter and set it to zero, they can cause the reference to be freed, leading to a use-after-free vulnerability. We recommend upgrading past commit 0323bce598eea038714f941ce2b22541c46d488f.

A use-after-free vulnerability was found in fw_set_parms in net/sched/cls_fw.c in network scheduler sub-component in the Linux Kernel. This issue occurs due to a missing sanity check during cleanup at the time of failure, leading to a misleading reference. This may allow a local attacker to gain local privilege escalation.

It was discovered that the IP-VLAN network driver for the Linux kernel did not properly initialize memory in some situations, leading to an out-of- bounds write vulnerability. An attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. It was discovered that the virtual terminal driver in the Linux kernel contained a use-after-free vulnerability. A local attacker could use this to cause a denial of service (system crash) or possibly expose sensitive information (kernel memory). Various other issues were also addressed.

*Credits: Muhammad Alifa Ramdhan of STAR Labs SG
CVSS Scores
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Attack Vector
Local
Attack Complexity
High
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Attack Vector
Local
Attack Complexity
Low
Authentication
Single
Confidentiality
Complete
Integrity
Complete
Availability
Complete
* Common Vulnerability Scoring System
SSVC
  • Decision:Track*
Exploitation
None
Automatable
No
Tech. Impact
Total
* Organization's Worst-case Scenario
Timeline
  • 2023-07-19 CVE Reserved
  • 2023-07-21 CVE Published
  • 2025-03-05 CVE Updated
  • 2025-03-30 EPSS Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-416: Use After Free
CAPEC
  • CAPEC-233: Privilege Escalation
Affected Vendors, Products, and Versions (5)