Linux: Use After Free
CVE-2026-64216 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 d4ae8dba90b89e7bb4d1045d1cb26afbaf13ee5c, 6080fa3ecfbb4448a3b47368629534c09b6ec750, 3866d015f33aeedf81338dd99154703bef33faef 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 0.46% 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 d4ae8dba90b89e7bb4d1045d1cb26afbaf13ee5c or 6080fa3ecfbb4448a3b47368629534c09b6ec750 or 3866d015f33aeedf81338dd99154703bef33faef or dbe556972100fabb8e5a1b3d2163831ff07b1e8e, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.18.34 or 7.0.11, 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 | ee4cdf7ba857a894ad1650d6ab77669cbbfa329e up to, but not including, d4ae8dba90b89e7bb4d1045d1cb26afbaf13ee5c; ee4cdf7ba857a894ad1650d6ab77669cbbfa329e up to, but not including, 6080fa3ecfbb4448a3b47368629534c09b6ec750; ee4cdf7ba857a894ad1650d6ab77669cbbfa329e up to, but not including, 3866d015f33aeedf81338dd99154703bef33faef; ee4cdf7ba857a894ad1650d6ab77669cbbfa329e up to, but not including, dbe556972100fabb8e5a1b3d2163831ff07b1e8e; 6.12 | d4ae8dba90b89e7bb4d1045d1cb26afbaf13ee5c, 6080fa3ecfbb4448a3b47368629534c09b6ec750, 3866d015f33aeedf81338dd99154703bef33faef, dbe556972100fabb8e5a1b3d2163831ff07b1e8e |
| Linux | Linux Kernel | 6.12 up to, but not including, 6.18.34; 6.19 up to, but not including, 7.0.11; 7.1 | 6.18.34, 7.0.11 |
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.
Official description
In 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.
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.
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Other references
Recent Use After Free vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
Spotted an error? Tell us.