Linux: Use After Free
CVE-2026-68162 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 19573dcddb8819fd68d6cd1f916c1c99c3fa4ff4, ceb7190b5c873d4a1267a1600c5aa52c600e929f, fd66854a22661929245f3d2b244c432bc8b1a150 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 0.2% 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 19573dcddb8819fd68d6cd1f916c1c99c3fa4ff4 or ceb7190b5c873d4a1267a1600c5aa52c600e929f or fd66854a22661929245f3d2b244c432bc8b1a150 or 158f3cc332dc53f43ec20060233d7c3cecd6d912, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 10c869a52f266e40f548cc3c565d14930a5edafc up to, but not including, 19573dcddb8819fd68d6cd1f916c1c99c3fa4ff4; dc583e7e5f8515ca489c0df28e4362a70eade382 up to, but not including, ceb7190b5c873d4a1267a1600c5aa52c600e929f; bd2a2939423566c654545fa3e96a656662a0af9e up to, but not including, fd66854a22661929245f3d2b244c432bc8b1a150; 1b67030d39f2b00f94ac1f0af11ba6657589e4d3 up to, but not including, 158f3cc332dc53f43ec20060233d7c3cecd6d912; 7ec30c54f339c640aa7e49d7e9f7bbed6bd42bf6 up to, but not including, 66700c0719675e0e118ae83b2d7168dacd69dd3d; c184bc621e3cef03ac9ba81a50dda2dae6a21d36 up to, but not including, 626bda8cfe43dff19a9833ff6ba055a817b5455c; 15649fd5415eda664ef35780c2013adeb5d9c695 up to, but not including, be6aae9d1b91c603adb35872d37d40e83daf8758; 15649fd5415eda664ef35780c2013adeb5d9c695 up to, but not including, a50e73488e0bbdd262b3be3c9a1d8dd078382381; and 8 more ranges | 19573dcddb8819fd68d6cd1f916c1c99c3fa4ff4, ceb7190b5c873d4a1267a1600c5aa52c600e929f, fd66854a22661929245f3d2b244c432bc8b1a150, 158f3cc332dc53f43ec20060233d7c3cecd6d912, 66700c0719675e0e118ae83b2d7168dacd69dd3d, 626bda8cfe43dff19a9833ff6ba055a817b5455c |
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 CNA.
Official description
In the Linux kernel, the following vulnerability has been resolved: sctp: avoid auth_enable sysctl UAF during netns teardown proc_sctp_do_auth() updates the SCTP control socket after changing net.sctp.auth_enable. The handler gets the per-net SCTP state from ctl->data, so an already opened sysctl file can still target a network namespace while that namespace is being torn down. SCTP previously registered its per-net sysctls from sctp_defaults_init(), while the control socket is created later from sctp_ctrlsock_init(). This exposed a window during initialization where auth_enable was writable before net->sctp.ctl_sock existed, and a teardown window where auth_enable stayed writable after inet_ctl_sock_destroy() had released the control socket. Move the per-net SCTP sysctl registration into sctp_ctrlsock_init() after sctp_ctl_sock_init() succeeds, and unregister the sysctl table before destroying the control socket in sctp_ctrlsock_exit(). If sysctl registration fails after the control socket was created, destroy the control socket in the same init path. Make sctp_sysctl_net_unregister() tolerate a missing header and clear the saved pointer so init-error and exit paths can safely share the unregister helper.
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/158f3cc332dc53f43ec20060233d7c3cecd6d912
- git.kernel.org/stable/c/19573dcddb8819fd68d6cd1f916c1c99c3fa4ff4
- git.kernel.org/stable/c/626bda8cfe43dff19a9833ff6ba055a817b5455c
- git.kernel.org/stable/c/66700c0719675e0e118ae83b2d7168dacd69dd3d
- git.kernel.org/stable/c/a50e73488e0bbdd262b3be3c9a1d8dd078382381
- git.kernel.org/stable/c/be6aae9d1b91c603adb35872d37d40e83daf8758
- git.kernel.org/stable/c/ceb7190b5c873d4a1267a1600c5aa52c600e929f
- git.kernel.org/stable/c/f8d5e7846025f4ab15a461235f8ebae9094a361a
- git.kernel.org/stable/c/fd66854a22661929245f3d2b244c432bc8b1a150
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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