vc_screen: reload vc pointer before if (ret) in vcs_write() to avoid UAF
In the Linux kernel, the following vulnerability has been resolved: vc_screen: reload vc pointer before if (ret) in vcs_write() to avoid UAF The reload of 'vc' added by commit 8fb9ea65c9d1 ("vc_screen: reload load of struct vc_data pointer in vcs_write() to avoid UAF") sits after the 'if (ret)' block, so the copy-failure break path exits the loop without reloading vc. If the vc was kfree()'d via vc_port_destruct during the unlocked copy_from_user() window, the post-loop 'if (written && vc) vcs_scr_updated(vc)' is reached with a stale non-NULL vc. The '&& vc' guard from commit a287620312dc ("vc_screen: fix null-ptr-deref in vcs_notifier() during concurrent vcs_write") only handles the NULL case, not this stale-non-NULL case; vcs_notifier() then reads param->vc->vc_num from freed memory: BUG: KASAN: slab-use-after-free in vcs_notifier+0x7c/0xd0 Read of size 2 at addr ffff888007149190 Call Trace: vcs_notifier+0x7c/0xd0 atomic_notifier_call_chain+0x70/0xa0 vcs_scr_updated+0x77/0xa0 vcs_write+0x71b/0x7e0 Allocated by task: vc_allocate -> con_install -> tty_open Freed by task: kfree <- vt_ioctl (VT_DISALLOCATE -> vc_port_destruct) Move the reload to immediately after console_lock(), before 'if (ret)', so every break path below passes a fresh vc to the post-loop vcs_scr_updated().
CVE-2026-98840
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-98840
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "8232fca738011ca2ec865b46ec721d1796dc0580",
"lessThan": "c073d01f6f5367c3a4f07efd507274ed0d03acd0",
"versionType": "git"
},
{
"status": "affected",
"version": "73049768ad57145acd337102c5aa3c788e6642c8",
"lessThan": "1485a3dd97ab1af2605243cabe6b604546d46dd1",
"versionType": "git"
},
{
"status": "affected",
"version": "7cc3dd79777f6ae4625ec37e84dd18a26dc88bde",
"lessThan": "233a2e190b12884d186027d0b86d43a48799b69c",
"versionType": "git"
},
{
"status": "affected",
"version": "a287620312dc6dcb9a093417a0e589bf30fcf38a",
"lessThan": "9dfcadc5e003fb250dd471db90144bd5366140e9",
"versionType": "git"
},
{
"status": "affected",
"version": "a287620312dc6dcb9a093417a0e589bf30fcf38a",
"lessThan": "226bd5603371cd9f6642cbb9e9a677f445de3530",
"versionType": "git"
},
{
"status": "affected",
"version": "43a6281790273c1b0a9ab76609ff0245b968f1e6",
"versionType": "git"
},
{
"status": "affected",
"version": "b6bbb85cf45bf0b070e741997fe0af3a772c5ad5",
"versionType": "git"
},
{
"status": "affected",
"version": "ff4806202749a51938236214adc0281481a57366",
"versionType": "git"
},
{
"status": "affected",
"version": "74be188eb2dc1c99d63986167b9a67d415fe7326",
"versionType": "git"
},
{
"status": "affected",
"version": "09a43e81279b8da15526da09877134b8bcf618b0",
"versionType": "git"
},
{
"status": "affected",
"version": "6.6.144",
"lessThan": "6.6.160",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.12.95",
"lessThan": "6.12.113",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.18.37",
"lessThan": "6.18.56",
"versionType": "semver"
},
{
"status": "affected",
"version": "5.10.260",
"lessThan": "5.11",
"versionType": "semver"
},
{
"status": "affected",
"version": "5.15.211",
"lessThan": "5.16",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.1.177",
"lessThan": "6.2",
"versionType": "semver"
},
{
"status": "affected",
"version": "7.0.14",
"lessThan": "7.1",
"versionType": "semver"
},
{
"status": "affected",
"version": "7.1.2",
"lessThan": "7.2",
"versionType": "semver"
}
],
"programFiles": [
"drivers/tty/vt/vc_screen.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "7.2"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "7.2",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.6.160",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.113",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.56",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.10",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"drivers/tty/vt/vc_screen.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-98840
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #49001 · Revision 1
- Added to Heist Feed
- Publisher date