Vulnerability in The NetBSD Foundation
CVE-2026-57843
NetBSD contains an information disclosure vulnerability in mm_open() within sys/dev/mm.c that allows unprivileged local users to obtain real kernel virtual addresses by opening world-accessible devices such as /dev/null or /dev/zero, which incorrectly receive the PK_KMEM process flag. Attackers can exploit this misconfigured flag to bypass the CANSEE_KPTR obfuscation mechanism and read kernel virtual addresses for sensitive kernel structures including struct proc, kauth_cred, filedesc, and vmspace via sysctl KERN_PROC queries.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N.
EPSS exploit prediction
EPSS: 0.001 (3.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 4th percentile — 3.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.001 · newest: 0.001 · change: 0.000
Affected products
Weakness classification (CWE)
References
- gnats.netbsd.org/60373 (vendor-advisory, patch)
- www.vulncheck.com/advisories/netbsd-mm-open-pk-kmem-flag-kernel-pointer-informa… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-57843?
- CVE-2026-57843 is a medium-severity vulnerability in The NetBSD Foundation, classified under Incorrect Permission Assignment for Critical Resource. CVSS score: 5.5/10. Published 2026-09-11.
- How severe is CVE-2026-57843?
- Medium severity. CVSS v3 base score is 5.5 out of 10.