high CVSS 7.7 EPSS <0.1%

CVE-2022-48651·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: ipvlan: Fix out-of-bound bugs caused by unset skb->mac_header If an AF_PACKET socket is used to send packets through ipvlan and the default xmit function of the AF_PACKET socket is changed from dev_queue_xmit() to packet_direct_xmit() via setsockopt() with the option name of PACKET_QDISC_BYPASS, the skb->mac_header may not be reset and remains as the initial value of 65535, this may trigger slab-out-of-bounds bugs as following: ================================================================= UG: KASAN: slab-out-of-bounds in ipvlan_xmit_mode_l2+0xdb/0x330 [ipvlan] PU: 2 PID: 1768 Comm: raw_send Kdump: loaded Not tainted 6.0.0-rc4+ #6 ardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1.fc33 all Trace: print_address_description.constprop.0+0x1d/0x160 print_report.cold+0x4f/0x112 kasan_report+0xa3/0x130 ipvlan_xmit_mode_l2+0xdb/0x330 [ipvlan] ipvlan_start_xmit+0x29/0xa0 [ipvlan] __dev_direct_xmit+0x2e2/0x380 packet_direct_xmit+0x22/0x60 packet_snd+0x7c9/0xc40 sock_sendmsg+0x9a/0xa0 __sys_sendto+0x18a/0x230 __x64_sys_sendto+0x74/0x90 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x63/0xcd The root cause is: 1. packet_snd() only reset skb->mac_header when sock->type is SOCK_RAW and skb->protocol is not specified as in packet_parse_headers() 2. packet_direct_xmit() doesn't reset skb->mac_header as dev_queue_xmit() In this case, skb->mac_header is 65535 when ipvlan_xmit_mode_l2() is called. So when ipvlan_xmit_mode_l2() gets mac header with eth_hdr() which use "skb->head + skb->mac_header", out-of-bound access occurs. This patch replaces eth_hdr() with skb_eth_hdr() in ipvlan_xmit_mode_l2() and reset mac header in multicast to solve this out-of-bound bug.

Severity
high
Software
Kernel
Fixed in
5.19.12
Published

How likely is exploitation

FIRST's Exploit Prediction Scoring System puts the probability of this CVE being exploited in the next 30 days at <0.1% — in the bottom 1% of all published CVEs. EPSS is an independent forecast of exploitation, not a severity rating: it says nothing about how much damage a successful attack does, which is what a CVSS score measures.

Read the two together. CVE-2022-48651 scores 7.7 on CVSS, so a successful attack would be serious — but at <0.1%, almost nobody is currently attempting it. That is a different situation from a flaw under mass exploitation, and it is usually the difference between patching on your next maintenance window and patching tonight.

Affected versions

From: 5.16

Until: 5.19.12

Fixed in: 5.19.12

How to fix this CVE

Update your Linux kernel to version 5.19.12 or later to patch the out-of-bounds memory access vulnerability in the ipvlan driver. This vulnerability affects systems using AF_PACKET sockets with QDISC_BYPASS enabled. Apply the kernel update immediately and reboot your system to complete the remediation.

sudo dnf update kernel kernel-devel

Defensia detects this vulnerability

How to check if you are affected

  1. Check current kernel version: uname -r (if version is between 5.16 and 5.19.11, system is vulnerable)
  2. Verify ipvlan driver is loaded: lsmod | grep ipvlan (if ipvlan module is present, the affected code path may be active)
  3. Search system logs for KASAN reports: grep -i 'KASAN.*slab-out-of-bounds' /var/log/kern.log or journalctl -u kernel | grep -i 'slab-out-of-bounds'
  4. Confirm fix applied: uname -r (should show 5.19.12 or later, or 5.20+ or 6.0+)

FAQ

What is CVE-2022-48651?

CVE-2022-48651 is a kernel vulnerability in the ipvlan driver that causes out-of-bounds memory access when AF_PACKET sockets bypass the QDISC layer. The uninitialized skb->mac_header field (set to 65535) triggers a slab buffer overflow when ipvlan processes packets.

Is CVE-2022-48651 being actively exploited?

No, this vulnerability is not listed in CISA's Known Exploited Vulnerabilities catalog and no public exploits are available. However, it can cause kernel crashes and potential privilege escalation on vulnerable systems.

What versions of Kernel are affected by CVE-2022-48651?

Linux kernel versions 5.16 through 5.19.11 are vulnerable. Versions 5.19.12 and later include the fix.

How do I check if my server is vulnerable to CVE-2022-48651?

Run 'uname -r' and check if the output shows a kernel version between 5.16 and 5.19.11. Additionally, verify ipvlan is loaded with 'lsmod | grep ipvlan'.

Does Defensia detect CVE-2022-48651?

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-2022-48651 will appear in your dashboard with remediation steps.

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References

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