high CVSS 7.8

CVE-2021-47605·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: vduse: fix memory corruption in vduse_dev_ioctl() The "config.offset" comes from the user. There needs to a check to prevent it being out of bounds. The "config.offset" and "dev->config_size" variables are both type u32. So if the offset if out of bounds then the "dev->config_size - config.offset" subtraction results in a very high u32 value. The out of bounds offset can result in memory corruption.

Severity
high
Software
Kernel
Fixed in
5.15.11
Published
2024-06-19

Affected versions

From: 5.15

Until: 5.15.11

Fixed in: 5.15.11

How to fix this CVE

Update your Linux kernel to version 5.15.11 or later to patch a critical memory corruption vulnerability in the vduse device driver. This flaw allows unprivileged local users to trigger out-of-bounds memory access through malformed ioctl requests. Immediate patching is recommended for systems running kernel 5.15.0 through 5.15.10 that have vduse enabled or loaded.

sudo dnf update kernel kernel-devel

Defensia detects this vulnerability

How to check if you are affected

  1. Step 1: Check your current kernel version with: uname -r (ensure it is not between 5.15.0 and 5.15.10)
  2. Step 2: Verify if vduse module is loaded: lsmod | grep vduse (if output is empty, component is not active)
  3. Step 3: Check system logs for ioctl errors related to vduse: grep -i 'vduse\|ioctl' /var/log/kern.log /var/log/messages 2>/dev/null | grep -i error
  4. Step 4: After patching, reboot and confirm fixed version: uname -r (should show 5.15.11 or later)

FAQ

What is CVE-2021-47605?

CVE-2021-47605 is a memory corruption vulnerability in the Linux kernel's vduse (Virtual Device User-Space Emulation) driver. An attacker with local user privileges can supply a malicious config offset value via ioctl that bypasses bounds validation, causing integer underflow and corrupting kernel memory.

Is CVE-2021-47605 being actively exploited?

No, according to CISA's Known Exploited Vulnerabilities (KEV) catalog, CVE-2021-47605 is not currently being actively exploited in the wild, and no public exploits have been released.

What versions of Kernel are affected by CVE-2021-47605?

Linux kernel versions 5.15.0 through 5.15.10 are vulnerable. The vulnerability was fixed in kernel version 5.15.11 and later.

How do I check if my server is vulnerable to CVE-2021-47605?

Run 'uname -r' to check your kernel version—if it shows 5.15.0 through 5.15.10, your system is vulnerable. Additionally, confirm vduse support with 'grep vduse /boot/config-$(uname -r)' (should show CONFIG_VDUSE=y or =m).

Does Defensia detect CVE-2021-47605?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If Linux kernel is installed on a monitored server, CVE-2021-47605 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-2022-48716CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: ASoC: codecs: wcd938x: fix incorrect used of portid Mixer controls have the channel id in mixer->reg, which is not same as port id. port id should be derived from chan_info array. So fix this. Without this, its possible that we could corrupt struct wcd938x_sdw_priv by accessing port_map array out of range with channel id instead of port id.

References

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