Linux: Use After Free
CVE-2026-68144 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 c4a52cb4da8d57d060b1d52085d25147a238dac2, df198743859fefba2f824115f8151dd62d7ad6d8, 1d81e19fc57a5ee55b4497d01bc0510d76fb9578 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 0.54% 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 c4a52cb4da8d57d060b1d52085d25147a238dac2 or df198743859fefba2f824115f8151dd62d7ad6d8 or 1d81e19fc57a5ee55b4497d01bc0510d76fb9578 or 8d931a75a38b9bb584a4071f5ebbd52755fc35ee, 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 | 9641458d3ec42def729fde64669abf07f3220cd5 up to, but not including, c4a52cb4da8d57d060b1d52085d25147a238dac2; 9641458d3ec42def729fde64669abf07f3220cd5 up to, but not including, df198743859fefba2f824115f8151dd62d7ad6d8; 9641458d3ec42def729fde64669abf07f3220cd5 up to, but not including, 1d81e19fc57a5ee55b4497d01bc0510d76fb9578; 9641458d3ec42def729fde64669abf07f3220cd5 up to, but not including, 8d931a75a38b9bb584a4071f5ebbd52755fc35ee; 9641458d3ec42def729fde64669abf07f3220cd5 up to, but not including, 17f78c0c0d41d738ee236eb6e841e39395188054; 9641458d3ec42def729fde64669abf07f3220cd5 up to, but not including, a48a889b60f73edb0399a8b08284a2ab0bd0295f; 9641458d3ec42def729fde64669abf07f3220cd5 up to, but not including, 25e3641beb51333bfbb155af2fd2573a61113af2; 9641458d3ec42def729fde64669abf07f3220cd5 up to, but not including, 0f71f852a96af9685858ce59fda34ecbf85c283d; and 1 more ranges | c4a52cb4da8d57d060b1d52085d25147a238dac2, df198743859fefba2f824115f8151dd62d7ad6d8, 1d81e19fc57a5ee55b4497d01bc0510d76fb9578, 8d931a75a38b9bb584a4071f5ebbd52755fc35ee, 17f78c0c0d41d738ee236eb6e841e39395188054, a48a889b60f73edb0399a8b08284a2ab0bd0295f |
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: phonet: pep: fix use-after-free in pep_get_sb() pep_get_sb() doesn't consider that pskb_may_pull() might have relocated the skb data, and continue to access the older pointer, causing UAF. Reproduced under KASAN: BUG: KASAN: slab-use-after-free in pep_get_sb+0x234/0x3b0 Read of size 1 at addr ff11000105510f50 by task repro/157 pep_get_sb+0x234/0x3b0 pipe_handler_do_rcv+0x5f7/0xa10 pep_do_rcv+0x203/0x410 __sk_receive_skb+0x471/0x4a0 phonet_rcv+0x5b3/0x6c0 __netif_receive_skb+0xcc/0x1d0 Refetch the header with skb_header_pointer() after pskb_may_pull(), so the possibly stale pointer is no longer dereferenced. There are better ways to solve this, but, this is the less instrusive one.
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
Other references
- git.kernel.org/stable/c/0f71f852a96af9685858ce59fda34ecbf85c283d
- git.kernel.org/stable/c/17f78c0c0d41d738ee236eb6e841e39395188054
- git.kernel.org/stable/c/1d81e19fc57a5ee55b4497d01bc0510d76fb9578
- git.kernel.org/stable/c/25e3641beb51333bfbb155af2fd2573a61113af2
- git.kernel.org/stable/c/8d931a75a38b9bb584a4071f5ebbd52755fc35ee
- git.kernel.org/stable/c/a48a889b60f73edb0399a8b08284a2ab0bd0295f
- git.kernel.org/stable/c/c4a52cb4da8d57d060b1d52085d25147a238dac2
- git.kernel.org/stable/c/df198743859fefba2f824115f8151dd62d7ad6d8
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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