Linux: Use After Free
CVE-2026-45972 is a critical-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 9.8 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 96e53bb3ee2f354cf6b4ab07bcc56e500f8b3f74, 7425453ea16dbc3bbb0f6cac4d60b537e5e4d151, 4d339b219004869e96c4ce56b8891f83a38da4c0 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 0.33% chance of exploitation within 30 days, which is low compared with other CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update Linux to 96e53bb3ee2f354cf6b4ab07bcc56e500f8b3f74 or 7425453ea16dbc3bbb0f6cac4d60b537e5e4d151 or 4d339b219004869e96c4ce56b8891f83a38da4c0 or e66dcf7bb9c4df5582c82bc3582725abcbfbea73, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.1.165 or 6.6.128 or 6.12.75 or 6.18.14, whichever matches your release line, or a later version.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 743f70406264348c0830f38409eb6c40a42fb2db up to, but not including, 96e53bb3ee2f354cf6b4ab07bcc56e500f8b3f74; 3a6d6b332f92990958602c1e35ce0173e2dd62e9 up to, but not including, 7425453ea16dbc3bbb0f6cac4d60b537e5e4d151; b64e3b5d8d759dd4333992e4ba4dadf9359952c8 up to, but not including, 4d339b219004869e96c4ce56b8891f83a38da4c0; 9ee608a64e37cea5b4b13e436c559dd0fb2ad1b5 up to, but not including, e66dcf7bb9c4df5582c82bc3582725abcbfbea73; e3a43633023e3cacaca60d4b8972d084a2b06236 up to, but not including, 639deb962986ef2f5e2a6d5a600c66f922471e81; e3a43633023e3cacaca60d4b8972d084a2b06236 up to, but not including, ebbbc4bfad4cb355d17c671223d0814ee3ef4eda; 6.1.163 up to, but not including, 6.1.165; 6.6.124 up to, but not including, 6.6.128; and 3 more ranges | 96e53bb3ee2f354cf6b4ab07bcc56e500f8b3f74, 7425453ea16dbc3bbb0f6cac4d60b537e5e4d151, 4d339b219004869e96c4ce56b8891f83a38da4c0, e66dcf7bb9c4df5582c82bc3582725abcbfbea73, 639deb962986ef2f5e2a6d5a600c66f922471e81, ebbbc4bfad4cb355d17c671223d0814ee3ef4eda |
| Red Hat | Red Hat Enterprise Linux 10 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 6 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 7 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 9 | Not specified in the record | Not stated |
| Linux | Linux Kernel | 6.1.163 up to, but not including, 6.1.165; 6.6.124 up to, but not including, 6.6.128; 6.12.70 up to, but not including, 6.12.75; 6.18.10 up to, but not including, 6.18.14; 6.19.1 up to, but not including, 6.19.4; 6.19 | 6.1.165, 6.6.128, 6.12.75, 6.18.14, 6.19.4 |
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
- 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
- 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:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CNA.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 9.8 | Critical | CNA |
| CVSS 3.1 | 7.0 | High | CNA |
Official description
In the Linux kernel, the following vulnerability has been resolved: smb: client: fix potential UAF and double free in smb2_open_file() Zero out @err_iov and @err_buftype before retrying SMB2_open() to prevent an UAF bug if @data != NULL, otherwise a double free.
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.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/4d339b219004869e96c4ce56b8891f83a38da4c0
- git.kernel.org/stable/c/639deb962986ef2f5e2a6d5a600c66f922471e81
- git.kernel.org/stable/c/7425453ea16dbc3bbb0f6cac4d60b537e5e4d151
- git.kernel.org/stable/c/96e53bb3ee2f354cf6b4ab07bcc56e500f8b3f74
- git.kernel.org/stable/c/e66dcf7bb9c4df5582c82bc3582725abcbfbea73
- git.kernel.org/stable/c/ebbbc4bfad4cb355d17c671223d0814ee3ef4eda
Other references
Recent Use After Free vulnerabilities
- 8.1 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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