CVE-2026-74270
Published: August 18, 2026Last modified: August 18, 2026
Description
In the Linux kernel, the following vulnerability has been resolved: handshake: Require admin permission for DONE command ACCEPT and DONE are the two downcalls of the handshake genl family, both intended for use by the trusted handshake agent (tlshd). ACCEPT already requires GENL_ADMIN_PERM; DONE has no privilege check at all. The fd-lookup in handshake_nl_done_doit() only confirms that some pending handshake request exists for the supplied sockfd; it does not authenticate the sender. An unprivileged process that guesses or observes a valid sockfd can therefore submit a DONE with HANDSHAKE_A_DONE_STATUS == 0, leaving the kernel consumer to proceed as if the handshake succeeded. A non-zero status on a forged DONE tears down a legitimate in-flight handshake before tlshd can report its real result.
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 7.8 |
| Attack Vector | LOCAL |
| Attack complexity | LOW |
| Privileges required | LOW |
| User interaction | NONE |
| Scope | UNCHANGED |
| Confidentiality | HIGH |
| Integrity impact | HIGH |
| Availability impact | HIGH |
| Vector | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
Status
| Product | Release | Package | Status |
|---|---|---|---|
| Alpaquita Linux | 23 LTS | linux-lts | Not affected (6.1.33-r0) |
| 25 LTS | linux-lts | Fixed (6.12.103-r0) | |
| Stream | linux-lts | Fixed (6.18.43-r0) |
References
- https://git.kernel.org/stable/c/25fb53e43ec006ac69b9e825a7e8a11d63a6083e
- https://git.kernel.org/stable/c/4dafc411948469277b276724c3b2b4408c02c04c
- https://git.kernel.org/stable/c/67cec2f1eb9e58719d622e92e2278ceda72dbd85
- https://git.kernel.org/stable/c/81246a65303d9635266b1334490142caaf86a11f
- https://git.kernel.org/stable/c/b6557f912509abe8e70223373dd7a44d1d4a0d6c