CVE-2023-0459 — Copy_from_user on 64-bit versions of the Linux kernel does not implement the __u

Copy_from_user on 64-bit versions of the Linux kernel does not implement the __uaccess_begin_nospec allowing a user to bypass the "access_ok" check and pass a kernel pointer to copy_from_user(). This would allow an attacker to leak information. We recommend upgrading be

01What is this vulnerability?

Copy_from_user on 64-bit versions of the Linux kernel does not implement the __uaccess_begin_nospec allowing a user to bypass the "access_ok" check and pass a kernel pointer to copy_from_user(). This would allow an attacker to leak information. We recommend upgrading beyond commit 74e19ef0ff8061ef55957c3abd71614ef0f42f47

02Affected products

Vendor	Product	Versions
Linux	Linux Kernel	4b842e4e25b12951fa10dedb4bc16bc47e3b850c

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2023-05-25T13:22:38.338Z
• Last modified: 2024-09-26T18:39:17.009Z

09References

• github.com — https://github.com/torvalds/linux/commit/4b842e4e25b12951fa10dedb4bc16bc47e3b850…
• github.com — https://github.com/torvalds/linux/commit/74e19ef0ff8061ef55957c3abd71614ef0f42f4…