Linux: Use After Free
CVE-2026-68140 is a high-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited from the same local network by an unauthenticated attacker, without any action from a user. The record lists versions 5f08c5e50bcb4680069bd3f9edd5728308816ded, c24faf11bd31bfe0500aca12cbdd5a573a954a5d, 99ddb33748698296a6f17b9b34aa3d16a406bb3c 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 0.27% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to 5f08c5e50bcb4680069bd3f9edd5728308816ded or c24faf11bd31bfe0500aca12cbdd5a573a954a5d or 99ddb33748698296a6f17b9b34aa3d16a406bb3c or 23658b350b4107e8292045c2044983fd426fa15d, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | f0703c80e5156406ad947cb67fe277725b48080f up to, but not including, 5f08c5e50bcb4680069bd3f9edd5728308816ded; f0703c80e5156406ad947cb67fe277725b48080f up to, but not including, c24faf11bd31bfe0500aca12cbdd5a573a954a5d; f0703c80e5156406ad947cb67fe277725b48080f up to, but not including, 99ddb33748698296a6f17b9b34aa3d16a406bb3c; f0703c80e5156406ad947cb67fe277725b48080f up to, but not including, 23658b350b4107e8292045c2044983fd426fa15d; f0703c80e5156406ad947cb67fe277725b48080f up to, but not including, a5bbaddf69853117f28173c3f5c8fc14c6b2ec82; f0703c80e5156406ad947cb67fe277725b48080f up to, but not including, 900cd6d8119b7f3ae5c4bf82f922ff5957df43db; f0703c80e5156406ad947cb67fe277725b48080f up to, but not including, f579582c03ed526281a8450159baf1d35099a85f; f0703c80e5156406ad947cb67fe277725b48080f up to, but not including, be7cc4656eb1f54029610e82d1f0fdd3f9b5ec0a; and 1 more ranges | 5f08c5e50bcb4680069bd3f9edd5728308816ded, c24faf11bd31bfe0500aca12cbdd5a573a954a5d, 99ddb33748698296a6f17b9b34aa3d16a406bb3c, 23658b350b4107e8292045c2044983fd426fa15d, a5bbaddf69853117f28173c3f5c8fc14c6b2ec82, 900cd6d8119b7f3ae5c4bf82f922ff5957df43db |
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
- AdjacentThe attacker must be on the same local network segment.
- 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:A/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: net/iucv: fix use-after-free of a severed iucv_path af_iucv queues not-yet-received message notifications on iucv->message_q, each holding a raw pointer to the connection's iucv_path. When the peer severs the connection, iucv_sever_path() frees that path with iucv_path_free() but leaves the notifications queued. A later recvmsg() drains message_q via iucv_process_message_q() and hands the stale path to message_receive() -- a use-after-free of the freed iucv_path. Drop the queued notifications when the path is severed; once the path is gone they can no longer be received. This also frees the notifications leaked when a socket is closed with messages still queued.
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: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other references
- git.kernel.org/stable/c/23658b350b4107e8292045c2044983fd426fa15d
- git.kernel.org/stable/c/5f08c5e50bcb4680069bd3f9edd5728308816ded
- git.kernel.org/stable/c/900cd6d8119b7f3ae5c4bf82f922ff5957df43db
- git.kernel.org/stable/c/99ddb33748698296a6f17b9b34aa3d16a406bb3c
- git.kernel.org/stable/c/a5bbaddf69853117f28173c3f5c8fc14c6b2ec82
- git.kernel.org/stable/c/be7cc4656eb1f54029610e82d1f0fdd3f9b5ec0a
- git.kernel.org/stable/c/c24faf11bd31bfe0500aca12cbdd5a573a954a5d
- git.kernel.org/stable/c/f579582c03ed526281a8450159baf1d35099a85f
Recent Use After Free vulnerabilities
- 7.8 High severity
- 9.8 Critical severity
- 7.5 High severity
- 8.8 High severity
- 7.8 High severity
- 7.8 High severity
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