CyberSecBulletin
CVE-2026-53199NVD status: Modified

Linux: NULL Pointer Dereference

Published Updated By the CyberSecBulletin desk

CVE-2026-53199 is a high-severity NULL pointer dereference vulnerability in Linux, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 16514afeb7d3d121072ba9a0b640d6c1c5507db0, a82d4251918f37d9c5aab7b365157669fb885ec3, 695c59cf7bf707e6ff8cea01916ee50e86616933 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.5% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to 16514afeb7d3d121072ba9a0b640d6c1c5507db0 or a82d4251918f37d9c5aab7b365157669fb885ec3 or 695c59cf7bf707e6ff8cea01916ee50e86616933 or 09b8a7aa5a341bb345dc492aac139525efa13515, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.10.259 or 5.15.210 or 6.1.176 or 6.6.143, whichever matches your release line, or a later version.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinuxc25aaf814a63f9d9c4e45416f13d70ef0aa0be2e up to, but not including, 16514afeb7d3d121072ba9a0b640d6c1c5507db0; c25aaf814a63f9d9c4e45416f13d70ef0aa0be2e up to, but not including, a82d4251918f37d9c5aab7b365157669fb885ec3; c25aaf814a63f9d9c4e45416f13d70ef0aa0be2e up to, but not including, 695c59cf7bf707e6ff8cea01916ee50e86616933; c25aaf814a63f9d9c4e45416f13d70ef0aa0be2e up to, but not including, 09b8a7aa5a341bb345dc492aac139525efa13515; c25aaf814a63f9d9c4e45416f13d70ef0aa0be2e up to, but not including, 918c0c988239aa5ab96b254e504d191af6191061; c25aaf814a63f9d9c4e45416f13d70ef0aa0be2e up to, but not including, 0b38870d81ab3a04c1ab0598d9d3285f5d9d0584; c25aaf814a63f9d9c4e45416f13d70ef0aa0be2e up to, but not including, fe7221b4346418d27ec2daccfc09df6692b76f0b; c25aaf814a63f9d9c4e45416f13d70ef0aa0be2e up to, but not including, 004e9ecfe6c5384f9e0b2f6f6389d42ec22789af; and 1 more ranges16514afeb7d3d121072ba9a0b640d6c1c5507db0, a82d4251918f37d9c5aab7b365157669fb885ec3, 695c59cf7bf707e6ff8cea01916ee50e86616933, 09b8a7aa5a341bb345dc492aac139525efa13515, 918c0c988239aa5ab96b254e504d191af6191061, 0b38870d81ab3a04c1ab0598d9d3285f5d9d0584
LinuxLinux Kernel3.16 up to, but not including, 5.10.259; 5.11 up to, but not including, 5.15.210; 5.16 up to, but not including, 6.1.176; 6.2 up to, but not including, 6.6.143; 6.7 up to, but not including, 6.12.94; 6.13 up to, but not including, 6.18.36; 6.19 up to, but not including, 7.0.13; 7.15.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.94, 6.18.36

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
NoneNo data is disclosed.
Integrity
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by CNA.

Official description

In the Linux kernel, the following vulnerability has been resolved: hv_netvsc: use kmap_local_page in netvsc_copy_to_send_buf netvsc_copy_to_send_buf() copies page buffer entries into the VMBus send buffer using phys_to_virt() on the entry PFN. Entries for the RNDIS header and the skb linear data come from kmalloc'd memory and are always in the kernel direct map, but entries for skb fragments reference page cache or user pages, which on 32-bit x86 with CONFIG_HIGHMEM=y can live above the LOWMEM boundary. For such a page phys_to_virt() returns an address outside the direct map and the subsequent memcpy() faults on the transmit softirq path, which is fatal. Map the pages with kmap_local_page() instead, handling two properties of the page buffer entries: - pb[i].pfn is a Hyper-V PFN at HV_HYP_PAGE_SIZE (4K) granularity, not a native PFN. Reconstruct the physical address first and derive the native page from it, so the mapping stays correct where PAGE_SIZE > HV_HYP_PAGE_SIZE (e.g. arm64 with 64K pages). - Since commit 41a6328b2c55 ("hv_netvsc: Preserve contiguous PFN grouping in the page buffer array"), an entry describes a full physically contiguous fragment and pb[i].len can exceed PAGE_SIZE, while kmap_local_page() maps a single page. Copy page by page, splitting at native page boundaries. The copy path only handles packets smaller than the send section size (6144 bytes by default); larger packets take the cp_partial path where only the RNDIS header is copied. So entries here are bounded by the section size and a copy is split at most once on 4K-page systems. On !CONFIG_HIGHMEM configs kmap_local_page() folds to page_address() and no mapping work is added.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: NULL Pointer Dereference

The product dereferences a pointer that it expects to be valid but is NULL.

How developers prevent this class of flaw

  • For any pointers that could have been modified or provided from a function that can return NULL, check the pointer for NULL before use. When working with a multithreaded or otherwise asynchronous environment, ensure that proper locking APIs are used to lock before the check, and unlock when it has finished.
  • Select a programming language that is not susceptible to these issues.
  • Check the results of all functions that return a value and verify that the value is non-null before acting upon it.

More NULL Pointer Dereference vulnerabilities (CWE-476)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Recent NULL Pointer Dereference vulnerabilities

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