CyberSecBulletin
CVE-2026-98116NVD status: Analyzed

Linux: Use After Free

Published Updated By the CyberSecBulletin desk

CVE-2026-98116 is a high-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions e6cdd2a0470d64073349a970dc1691433804b271, 9857a75714bb5df4781e4d8b1a1753b1e17bf07a, cbadf2575d25e7dcc0d4da2717817ae569fbc99b 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 0.13% 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 e6cdd2a0470d64073349a970dc1691433804b271 or 9857a75714bb5df4781e4d8b1a1753b1e17bf07a or cbadf2575d25e7dcc0d4da2717817ae569fbc99b or cbc7ec97601d09b74e05e44470fa6b0bcdabf3f5, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 4.15 or 4.20 or 5.5 or 5.11, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux33061d0fba51d2bf70a2ef9645f703c33fe8e438 up to, but not including, e6cdd2a0470d64073349a970dc1691433804b271; 92ee3c60ec9fe64404dc035e7c41277d74aa26cb up to, but not including, 9857a75714bb5df4781e4d8b1a1753b1e17bf07a; 92ee3c60ec9fe64404dc035e7c41277d74aa26cb up to, but not including, cbadf2575d25e7dcc0d4da2717817ae569fbc99b; 92ee3c60ec9fe64404dc035e7c41277d74aa26cb up to, but not including, cbc7ec97601d09b74e05e44470fa6b0bcdabf3f5; 92ee3c60ec9fe64404dc035e7c41277d74aa26cb up to, but not including, fd137bf8149bc6460f9b7b1fc292025da04cb9ee; 92ee3c60ec9fe64404dc035e7c41277d74aa26cb up to, but not including, 8c1882dfee8f404d118020664b73eb4592172226; 92ee3c60ec9fe64404dc035e7c41277d74aa26cb up to, but not including, 9b110a9dcecc59516c77cb3c0caf1f492f75df2d; a42aa926843acca96c0dfbde2e835b8137f2f092; and 13 more rangese6cdd2a0470d64073349a970dc1691433804b271, 9857a75714bb5df4781e4d8b1a1753b1e17bf07a, cbadf2575d25e7dcc0d4da2717817ae569fbc99b, cbc7ec97601d09b74e05e44470fa6b0bcdabf3f5, fd137bf8149bc6460f9b7b1fc292025da04cb9ee, 8c1882dfee8f404d118020664b73eb4592172226
LinuxLinux Kernel4.14.279 up to, but not including, 4.15; 4.19.243 up to, but not including, 4.20; 5.4.193 up to, but not including, 5.5; 5.10.109 up to, but not including, 5.11; 5.15.32 up to, but not including, 5.15.222; 5.16.18 through 5.17.1; 6.7 up to, but not including, 6.12.111; 6.13 up to, but not including, 6.18.53; and 2 more ranges4.15, 4.20, 5.5, 5.11, 5.15.222, 6.12.111

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
LocalThe attacker needs local access or must trick a user into running something.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

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

Official description

In the Linux kernel, the following vulnerability has been resolved: ALSA: pcm: Serialize PCM mmap with buffer reallocation to fix page UAF snd_pcm_hw_params() and snd_pcm_hw_free() guard buffer reallocation with an mmap_count check performed under the PCM stream lock, but the lock is released long before the buffer is actually freed: snd_pcm_sync_stop(), constraint refinement and do_free_pages() all happen in between. snd_pcm_mmap_data(), on the other hand, takes no lock at all: it validates against the old buffer's state and dma_bytes, remaps its pages into the VMA, and only then increments mmap_count. A concurrent mmap() can therefore slip in between the check and the free. remap_pfn_range() installs writable PTEs for the old buffer's pages without taking page references, and the subsequent do_free_pages() returns those pages to the page allocator while the VMA still maps them. This leaves a stale, writable mapping of freed pages: a page-level use-after-free that can be leveraged for local privilege escalation. Make snd_pcm_mmap_data() participate in the buffer-access scheme introduced for hw_params/hw_free: acquire runtime->buffer_accessing before validating and remapping, and release it afterwards. Buffer reallocation already fails with -EBUSY while accessors are active, and the mmap side now fails with -EBUSY while a reallocation is in progress, so the validate/remap sequence and the check/free sequence can no longer interleave. A reproducer that turns this race into a stale writable mapping of the freed DMA buffer pages is available on request.

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

The underlying weakness: Use After Free

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.

How developers prevent this class of flaw

  • Choose a language that provides automatic memory management.
  • When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.

More Use After Free vulnerabilities (CWE-416)

Timeline

  1. CVE record published.
  2. Record last changed materially (score, affected products, status or references).

References

Recent Use After Free vulnerabilities

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