CyberSecBulletin
CVE-2026-45998NVD status: Modified

Linux: Use After Free

Published Updated By the CyberSecBulletin desk

CVE-2026-45998 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 e3bf143b1e98fb3d6d9e6825bcd683974d478e8c, bf20f46d94f1db38e6ffc0ca204a5fe0de01b495, 996b0487b3cdda4c91811dbb1c9564626bc840bd 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 0.14% 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 e3bf143b1e98fb3d6d9e6825bcd683974d478e8c or bf20f46d94f1db38e6ffc0ca204a5fe0de01b495 or 996b0487b3cdda4c91811dbb1c9564626bc840bd or 8fde6296c4d4da2be7ab761305ab7f232b94eefd, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 6.6.140 or 6.12.86 or 6.18.27 or 7.0.4, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux2d1faf7a0ca3c0b327cf064c80e4e775532c9319 up to, but not including, e3bf143b1e98fb3d6d9e6825bcd683974d478e8c; 2d1faf7a0ca3c0b327cf064c80e4e775532c9319 up to, but not including, bf20f46d94f1db38e6ffc0ca204a5fe0de01b495; 2d1faf7a0ca3c0b327cf064c80e4e775532c9319 up to, but not including, 996b0487b3cdda4c91811dbb1c9564626bc840bd; 2d1faf7a0ca3c0b327cf064c80e4e775532c9319 up to, but not including, 8fde6296c4d4da2be7ab761305ab7f232b94eefd; 2d1faf7a0ca3c0b327cf064c80e4e775532c9319 up to, but not including, 1f2740150f904bfa60e4bad74d65add3ccb5e7f8; 6.2e3bf143b1e98fb3d6d9e6825bcd683974d478e8c, bf20f46d94f1db38e6ffc0ca204a5fe0de01b495, 996b0487b3cdda4c91811dbb1c9564626bc840bd, 8fde6296c4d4da2be7ab761305ab7f232b94eefd, 1f2740150f904bfa60e4bad74d65add3ccb5e7f8
Red HatRed Hat Enterprise Linux 10Not specified in the recordNot stated
Red HatRed Hat Enterprise Linux 10.0 Extended Update SupportNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 9.2 Update Services for SAP SolutionsNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 9.4 Update Services for SAP SolutionsNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 9.6 Extended Update SupportNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 6Not specified in the recordNot stated
Red HatRed Hat Enterprise Linux 7Not specified in the recordNot stated
Red HatRed Hat Enterprise Linux 8Not specified in the recordNot stated
Red HatRed Hat Enterprise Linux 9Not specified in the recordNot stated
LinuxLinux Kernel6.2 up to, but not including, 6.6.140; 6.7 up to, but not including, 6.12.86; 6.13 up to, but not including, 6.18.27; 6.19 up to, but not including, 7.0.46.6.140, 6.12.86, 6.18.27, 7.0.4

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 NVD.

Scoring systemScoreSeverityScored by
CVSS 3.17.8HighNVD
CVSS 3.17.0HighCNA

Official description

In the Linux kernel, the following vulnerability has been resolved: rxrpc: Fix potential UAF after skb_unshare() failure If skb_unshare() fails to unshare a packet due to allocation failure in rxrpc_input_packet(), the skb pointer in the parent (rxrpc_io_thread()) will be NULL'd out. This will likely cause the call to trace_rxrpc_rx_done() to oops. Fix this by moving the unsharing down to where rxrpc_input_call_event() calls rxrpc_input_call_packet(). There are a number of places prior to that where we ignore DATA packets for a variety of reasons (such as the call already being complete) for which an unshare is then avoided. And with that, rxrpc_input_packet() doesn't need to take a pointer to the pointer to the packet, so change that to just a pointer.

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. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Use After Free vulnerabilities

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