Invalid kernel-memory read via stale console pointer
Published Oct 18, 2026 · Updated Oct 18, 2026
Use-after-free in Linux vc_screen allows local users to trigger an invalid kernel-memory read through virtual-console writes. The copy-failure exit in vcs_write() skips refreshing vc after copy_from_user(), so vcs_notifier() reads vc_num from a console freed concurrently by VT_DISALLOCATE. Triggering requires console-device write access, prior partial output and concurrent console teardown; the disclosed result is a stale-memory read, not demonstrated privilege escalation or data disclosure.
Summary
What happened
Use-after-free in Linux vc_screen allows local users to trigger an invalid kernel-memory read through virtual-console writes. The copy-failure exit in vcs_write() skips refreshing vc after copy_from_user(), so vcs_notifier() reads vc_num from a console freed concurrently by VT_DISALLOCATE. Triggering requires console-device write access, prior partial output and concurrent console teardown; the disclosed result is a stale-memory read, not demonstrated privilege escalation or data disclosure.
The record
- CVE
- CVE-2026-98840
- Published
- Oct 18, 2026
- Updated
- Oct 18, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- Unavailable
- Attack vector
- local
- Privileges
- Unavailable
Timeline
How it unfolded
- Oct 18, 2026CVE publishedPublication date reported by the CVE source.
- Oct 18, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=09a43e81279b8da15526da09877134b8bcf618b0
- Affected versionversion=43a6281790273c1b0a9ab76609ff0245b968f1e6
- Affected versionversion=5.10.260 <5.11
- Affected versionversion=5.15.211 <5.16
- Affected versionversion=6.1.177 <6.2
- Affected versionversion=6.12.95 <6.12.113
- Affected versionversion=6.18.37 <6.18.56
- Affected versionversion=6.6.144 <6.7
- Affected versionversion=7.0.14 <7.1
- Affected versionversion=7.1.2 <7.2
- Affected versionversion=7.2
- Affected versionversion=73049768ad57145acd337102c5aa3c788e6642c8 <1485a3dd97ab1af2605243cabe6b604546d46dd1
- Affected versionversion=74be188eb2dc1c99d63986167b9a67d415fe7326
- Affected versionversion=7cc3dd79777f6ae4625ec37e84dd18a26dc88bde <233a2e190b12884d186027d0b86d43a48799b69c
- Affected versionversion=8232fca738011ca2ec865b46ec721d1796dc0580
- Affected versionversion=a287620312dc6dcb9a093417a0e589bf30fcf38a <226bd5603371cd9f6642cbb9e9a677f445de3530
- Affected versionversion=a287620312dc6dcb9a093417a0e589bf30fcf38a <9dfcadc5e003fb250dd471db90144bd5366140e9
- Affected versionversion=b6bbb85cf45bf0b070e741997fe0af3a772c5ad5
- Affected versionversion=ff4806202749a51938236214adc0281481a57366
What conditions does exploitation require?
What is affected?
Published CVSS scores
No CVSS assessment is available in this record.
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Activity data is delayed. The latest report is Sep 28, 2026.
Weakness, pattern, technique
No sourced classifications are available.
Public exploit references
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Technologies
Your stack
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