high CVSS 7.1

CVE-2021-47160·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: net: dsa: mt7530: fix VLAN traffic leaks PCR_MATRIX field was set to all 1's when VLAN filtering is enabled, but was not reset when it is disabled, which may cause traffic leaks: ip link add br0 type bridge vlan_filtering 1 ip link add br1 type bridge vlan_filtering 1 ip link set swp0 master br0 ip link set swp1 master br1 ip link set br0 type bridge vlan_filtering 0 ip link set br1 type bridge vlan_filtering 0 # traffic in br0 and br1 will start leaking to each other As port_bridge_{add,del} have set up PCR_MATRIX properly, remove the PCR_MATRIX write from mt7530_port_set_vlan_aware.

Severity
high
Software
Kernel
Fixed in
5.12.9
Published
2024-03-25

Affected versions

From: 5.11

Until: 5.12.9

Fixed in: 5.12.9

How to fix this CVE

Update your Linux kernel to version 5.12.9 or later to resolve this VLAN traffic isolation vulnerability in Mediatek MT7530 switch driver. The issue occurs when VLAN filtering is disabled after being enabled, leaving port matrix configuration in an unsafe state that allows inter-VLAN traffic leakage. Apply the kernel update through your distribution's package manager and reboot to complete the remediation.

sudo dnf update kernel kernel-devel && sudo reboot

Defensia detects this vulnerability

How to check if you are affected

  1. Check your kernel version with: uname -r — compare against 5.12.9 (if version is 5.11.x through 5.12.8, you are vulnerable)
  2. Verify if your system uses Mediatek MT7530 switch hardware with: lspci -k | grep -i mediatek or ethtool -i eth0 | grep driver (look for mt7530 driver)
  3. Check kernel logs for VLAN-related errors or configuration messages: sudo dmesg | grep -i vlan | grep -i mt7530
  4. Validate the fix by checking kernel version post-update with: uname -r (should be 5.12.9 or higher, and dmesg should show 'mt7530.*bridge' initialization without matrix reset warnings)

FAQ

What is CVE-2021-47160?

CVE-2021-47160 is a network isolation bypass vulnerability in the Linux kernel's Mediatek MT7530 DSA driver where the port forwarding matrix is not properly reset when VLAN filtering is disabled, allowing traffic intended for one VLAN to leak into another.

Is CVE-2021-47160 being actively exploited?

No, this vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog and no public exploit code is available.

What versions of Kernel are affected by CVE-2021-47160?

Kernel versions 5.11 through 5.12.8 are affected; version 5.12.9 and later contain the fix.

How do I check if my server is vulnerable to CVE-2021-47160?

Run 'uname -r' to check your kernel version; if it returns 5.11.x through 5.12.8, verify if MT7530 hardware is present with 'lspci -k | grep -i mediatek' — if both conditions are true, you are vulnerable.

Does Defensia detect CVE-2021-47160?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If the Linux kernel is installed on a monitored server, CVE-2021-47160 will appear in your dashboard with remediation steps.

Related Kernel CVEs

CVE-2024-42256CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: cifs: Fix server re-repick on subrequest retry When a subrequest is marked for needing retry, netfs will call cifs_prepare_write() which will make cifs repick the server for the op before renegotiating credits; it then calls cifs_issue_write() which invokes smb2_async_writev() - which re-repicks the server. If a different server is then selected, this causes the increment of server->in_flight to happen against one record and the decrement to happen against another, leading to misaccounting. Fix this by just removing the repick code in smb2_async_writev(). As this is only called from netfslib-driven code, cifs_prepare_write() should always have been called first, and so server should never be NULL and the preparatory step is repeated in the event that we do a retry. The problem manifests as a warning looking something like: WARNING: CPU: 4 PID: 72896 at fs/smb/client/smb2ops.c:97 smb2_add_credits+0x3f0/0x9e0 [cifs] ... RIP: 0010:smb2_add_credits+0x3f0/0x9e0 [cifs] ... smb2_writev_callback+0x334/0x560 [cifs] cifs_demultiplex_thread+0x77a/0x11b0 [cifs] kthread+0x187/0x1d0 ret_from_fork+0x34/0x60 ret_from_fork_asm+0x1a/0x30 Which may be triggered by a number of different xfstests running against an Azure server in multichannel mode. generic/249 seems the most repeatable, but generic/215, generic/249 and generic/308 may also show it.
CVE-2024-36031CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: keys: Fix overwrite of key expiration on instantiation The expiry time of a key is unconditionally overwritten during instantiation, defaulting to turn it permanent. This causes a problem for DNS resolution as the expiration set by user-space is overwritten to TIME64_MAX, disabling further DNS updates. Fix this by restoring the condition that key_set_expiry is only called when the pre-parser sets a specific expiry.
CVE-2024-38612CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: ipv6: sr: fix invalid unregister error path The error path of seg6_init() is wrong in case CONFIG_IPV6_SEG6_LWTUNNEL is not defined. In that case if seg6_hmac_init() fails, the genl_unregister_family() isn't called. This issue exist since commit 46738b1317e1 ("ipv6: sr: add option to control lwtunnel support"), and commit 5559cea2d5aa ("ipv6: sr: fix possible use-after-free and null-ptr-deref") replaced unregister_pernet_subsys() with genl_unregister_family() in this error path.
CVE-2024-38623CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: fs/ntfs3: Use variable length array instead of fixed size Should fix smatch warning: ntfs_set_label() error: __builtin_memcpy() 'uni->name' too small (20 vs 256)
CVE-2021-47548CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: ethernet: hisilicon: hns: hns_dsaf_misc: fix a possible array overflow in hns_dsaf_ge_srst_by_port() The if statement: if (port >= DSAF_GE_NUM) return; limits the value of port less than DSAF_GE_NUM (i.e., 8). However, if the value of port is 6 or 7, an array overflow could occur: port_rst_off = dsaf_dev->mac_cb[port]->port_rst_off; because the length of dsaf_dev->mac_cb is DSAF_MAX_PORT_NUM (i.e., 6). To fix this possible array overflow, we first check port and if it is greater than or equal to DSAF_MAX_PORT_NUM, the function returns.

References

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