high CVSS 7.8

CVE-2022-48771·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: drm/vmwgfx: Fix stale file descriptors on failed usercopy A failing usercopy of the fence_rep object will lead to a stale entry in the file descriptor table as put_unused_fd() won't release it. This enables userland to refer to a dangling 'file' object through that still valid file descriptor, leading to all kinds of use-after-free exploitation scenarios. Fix this by deferring the call to fd_install() until after the usercopy has succeeded.

Severity
high
Software
Kernel
Fixed in
5.16.4
Published
2024-06-20

Affected versions

From: 5.16

Until: 5.16.4

Fixed in: 5.16.4

How to fix this CVE

Update your Linux kernel to version 5.16.4 or later to patch a critical file descriptor management flaw in the DRM/vmwgfx subsystem. This vulnerability allows unprivileged local users to retain access to kernel file objects after failed operations, creating a pathway for use-after-free exploits. Immediate patching is recommended for systems running kernel versions 5.16 through 5.16.3.

sudo dnf update kernel kernel-devel

Defensia detects this vulnerability

How to check if you are affected

  1. Run 'uname -r' to check your current kernel version and confirm if it falls within the 5.16.0 to 5.16.3 range
  2. Verify vmwgfx driver is loaded with 'lsmod | grep vmwgfx' — if present, your system uses the affected code path
  3. Search system logs for fence_rep or usercopy failures with 'sudo journalctl -b | grep -i "fence\|usercopy"' to detect exploitation attempts
  4. After patching, run 'uname -r' again and confirm the kernel version is 5.16.4 or newer to verify the fix is active

FAQ

What is CVE-2022-48771?

This vulnerability exists in the Linux kernel's vmwgfx (VMware graphics) driver where a failed data copy operation leaves a valid file descriptor pointing to a freed kernel object, enabling local privilege escalation through use-after-free attacks.

Is CVE-2022-48771 being actively exploited?

No — this vulnerability is not listed in the CISA KEV catalog and no public exploits are documented, though the high CVSS score (7.8) indicates significant potential if weaponized.

What versions of Kernel are affected by CVE-2022-48771?

Linux kernel versions 5.16.0 through 5.16.3 are affected; version 5.16.4 and later include the fix.

How do I check if my server is vulnerable to CVE-2022-48771?

Run 'uname -r' to display your kernel version — if it shows 5.16.0, 5.16.1, 5.16.2, or 5.16.3, you are vulnerable.

Does Defensia detect CVE-2022-48771?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If the Linux kernel is installed on a monitored server running versions 5.16.0–5.16.3, CVE-2022-48771 will appear in your dashboard with remediation steps.

Related Kernel CVEs

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CVE-2026-64355CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: bpf: Reject fragmented frames in devmap Devmap broadcast redirects clone the packet for all but the last destination. For native XDP, that clone path copies only the linear xdp_frame data, while fragmented frames keep skb_shared_info in tailroom outside the linear area. Cloning such a frame leaves XDP_FLAGS_HAS_FRAGS set but without valid frag metadata, and the later free path can interpret uninitialized tail data as skb_shared_info, leading to an out-of-bounds access during frame return. Reject fragmented native XDP frames in dev_map_enqueue_clone(). Add the same restriction to the generic XDP clone path in dev_map_redirect_clone(). Generic XDP represents fragmented packets as nonlinear skbs, and rejecting them here keeps clone-based broadcast support aligned between native and generic XDP.
CVE-2026-63993CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: vxlan: do not reuse cached ip_hdr() value after skb_tunnel_check_pmtu() skb_tunnel_check_pmtu() can change skb->head. Reusing old_iph afer skb_tunnel_check_pmtu() can cause an UAF. Use instead ip_hdr(skb) as done in drivers/net/bareudp.c and drivers/net/geneve.c. Found by Sashiko.
CVE-2026-43501CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: ipv6: rpl: reserve mac_len headroom when recompressed SRH grows ipv6_rpl_srh_rcv() decompresses an RFC 6554 Source Routing Header, swaps the next segment into ipv6_hdr->daddr, recompresses, then pulls the old header and pushes the new one plus the IPv6 header back. The recompressed header can be larger than the received one when the swap reduces the common-prefix length the segments share with daddr (CmprI=0, CmprE>0, seg[0][0] != daddr[0] gives the maximum +8 bytes). pskb_expand_head() was gated on segments_left == 0, so on earlier segments the push consumed unchecked headroom. Once skb_push() leaves fewer than skb->mac_len bytes in front of data, skb_mac_header_rebuild()'s call to: skb_set_mac_header(skb, -skb->mac_len); will store (data - head) - mac_len into the u16 mac_header field, which wraps to ~65530, and the following memmove() writes mac_len bytes ~64KiB past skb->head. A single AF_INET6/SOCK_RAW/IPV6_HDRINCL packet over lo with a two segment type-3 SRH (CmprI=0, CmprE=15) reaches headroom 8 after one pass; KASAN reports a 14-byte OOB write in ipv6_rthdr_rcv. Fix this by expanding the head whenever the remaining room is less than the push size plus mac_len, and request that much extra so the rebuilt MAC header fits afterwards.
CVE-2026-64216CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: netfs: Fix potential UAF in netfs_unlock_abandoned_read_pages() netfs_unlock_abandoned_read_pages(rreq) accesses the index of the folios it is wanting to unlock and compares that to rreq->no_unlock_folio so that it doesn't unlock a folio being read for netfs_perform_write() or netfs_write_begin(). However, given that netfs_unlock_abandoned_read_pages() is called _after_ NETFS_RREQ_IN_PROGRESS is cleared, the one folio that it's not allowed to dereference is the one specified by ->no_unlock_folio as ownership immediately reverts to the caller. Fix this by storing the folio pointer instead and using that rather than the index. Also fix netfs_unlock_read_folio() where the same applies.

References

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