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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2021-47555 Detail

Description

In the Linux kernel, the following vulnerability has been resolved: net: vlan: fix underflow for the real_dev refcnt Inject error before dev_hold(real_dev) in register_vlan_dev(), and execute the following testcase: ip link add dev dummy1 type dummy ip link add name dummy1.100 link dummy1 type vlan id 100 ip link del dev dummy1 When the dummy netdevice is removed, we will get a WARNING as following: ======================================================================= refcount_t: decrement hit 0; leaking memory. WARNING: CPU: 2 PID: 0 at lib/refcount.c:31 refcount_warn_saturate+0xbf/0x1e0 and an endless loop of: ======================================================================= unregister_netdevice: waiting for dummy1 to become free. Usage count = -1073741824 That is because dev_put(real_dev) in vlan_dev_free() be called without dev_hold(real_dev) in register_vlan_dev(). It makes the refcnt of real_dev underflow. Move the dev_hold(real_dev) to vlan_dev_init() which is the call-back of ndo_init(). That makes dev_hold() and dev_put() for vlan's real_dev symmetrical.


Metrics

 
NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://git.kernel.org/stable/c/01d9cc2dea3fde3bad6d27f464eff463496e2b00 CVE, kernel.org Patch 
https://git.kernel.org/stable/c/5e44178864b38dd70b877985abd7d86fdb95f27d CVE, kernel.org Patch 
https://git.kernel.org/stable/c/6e800ee43218a56acc93676bbb3d93b74779e555 CVE, kernel.org Patch 
https://git.kernel.org/stable/c/f7fc72a508cf115c273a7a29350069def1041890 CVE, kernel.org Patch 

Weakness Enumeration

CWE-ID CWE Name Source
CWE-191 Integer Underflow (Wrap or Wraparound) cwe source acceptance level NIST  

Known Affected Software Configurations Switch to CPE 2.2

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Change History

5 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2021-47555
NVD Published Date:
05/24/2024
NVD Last Modified:
09/18/2025
Source:
kernel.org