fbdev: fbcon: fix out-of-bounds read in err_out of fbcon_do_set_font()
In the Linux kernel, the following vulnerability has been resolved: fbdev: fbcon: fix out-of-bounds read in err_out of fbcon_do_set_font() When fbcon_do_set_font() fails (e.g., due to a memory allocation failure inside vc_resize() under heavy memory pressure), it jumps to the `err_out` label to roll back the console state. However, the current rollback logic forgets to restore the `hi_font` state, leading to a severe state machine corruption. Earlier in the function, `set_vc_hi_font()` might be called to change `vc->vc_hi_font_mask` and mutate the screen buffer. If `vc_resize()` subsequently fails, the `err_out` path restores `vc_font.charcount` but entirely skips rolling back the `vc_hi_font_mask` and the screen buffer. This mismatch leaves the terminal in a desynchronized state. Because `vc_hi_font_mask` remains set, the VT subsystem will still accept character indices greater than 255 from userspace and write them to the screen buffer. Subsequent rendering calls (e.g., `fbcon_putcs()`) will then use these inflated indices to access the reverted, 256-character font array, leading to a deterministic out-of-bounds read and potential kernel memory disclosure. Fix this by adding the missing rollback logic for the `hi_font` mask and screen buffer in the error path.
- Products
- Kernel
- Affected versions
- Not specified
- Fixed versions
- 5.10.261, 5.15.212, 6.1.178, 6.12.96, 6.18.39, 6.6.145, 7.1.3
- CVEs
- CVE-2026-53402
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 6 Nov 2026, 01:40 UTC · Revision 1
Source evidence
fbdev: fbcon: fix out-of-bounds read in err_out of fbcon_do_set_font()
core-osv · Original sourcePublished 19 Jul 2026, 12:02 UTC
In the Linux kernel, the following vulnerability has been resolved: fbdev: fbcon: fix out-of-bounds read in err_out of fbcon_do_set_font() When fbcon_do_set_font() fails (e.g., due to a memory allocation failure inside vc_resize() under heavy memory pressure), it jumps to the `err_out` label to roll back the console state. However, the current rollback logic forgets to restore the `hi_font` state, leading to a severe state machine corruption. Earlier in the function, `set_vc_hi_font()` might be called to change `vc->vc_hi_font_mask` and mutate the screen buffer. If `vc_resize()` subsequently fails, the `err_out` path restores `vc_font.charcount` but entirely skips rolling back the `vc_hi_font_mask` and the screen buffer. This mismatch leaves the terminal in a desynchronized state. Because `vc_hi_font_mask` remains set, the VT subsystem will still accept character indices greater than 255 from userspace and write them to the screen buffer. Subsequent rendering calls (e.g., `fbcon_putcs()`) will then use these inflated indices to access the reverted, 256-character font array, leading to a deterministic out-of-bounds read and potential kernel memory disclosure. Fix this by adding the missing rollback logic for the `hi_font` mask and screen buffer in the error path.
osv:CVE-2026-53402
Kernel
Fixed versions: 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.96, 6.18.39, 7.1.3
Complete source record
{
"id": "ec24d46975e10ec4344b4aa568d61bb9c2104eee277ca98d2e84d2c3506fa93e",
"url": "https://osv.dev/vulnerability/CVE-2026-53402",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "fbdev: fbcon: fix out-of-bounds read in err_out of fbcon_do_set_font()",
"summary": "In the Linux kernel, the following vulnerability has been resolved: fbdev: fbcon: fix out-of-bounds read in err_out of fbcon_do_set_font() When fbcon_do_set_font() fails (e.g., due to a memory allocation failure inside vc_resize() under heavy memory pressure), it jumps to the `err_out` label to roll back the console state. However, the current rollback logic forgets to restore the `hi_font` state, leading to a severe state machine corruption. Earlier in the function, `set_vc_hi_font()` might be called to change `vc->vc_hi_font_mask` and mutate the screen buffer. If `vc_resize()` subsequently fails, the `err_out` path restores `vc_font.charcount` but entirely skips rolling back the `vc_hi_font_mask` and the screen buffer. This mismatch leaves the terminal in a desynchronized state. Because `vc_hi_font_mask` remains set, the VT subsystem will still accept character indices greater than 255 from userspace and write them to the screen buffer. Subsequent rendering calls (e.g., `fbcon_putcs()`) will then use these inflated indices to access the reverted, 256-character font array, leading to a deterministic out-of-bounds read and potential kernel memory disclosure. Fix this by adding the missing rollback logic for the `hi_font` mask and screen buffer in the error path.",
"evidence": "osv:CVE-2026-53402",
"products": [
{
"name": {
"value": "Kernel",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "5.10.261",
"evidence": "/affected/1/ranges"
},
{
"value": "5.15.212",
"evidence": "/affected/1/ranges"
},
{
"value": "6.1.178",
"evidence": "/affected/1/ranges"
},
{
"value": "6.6.145",
"evidence": "/affected/1/ranges"
},
{
"value": "6.12.96",
"evidence": "/affected/1/ranges"
},
{
"value": "6.18.39",
"evidence": "/affected/1/ranges"
},
{
"value": "7.1.3",
"evidence": "/affected/1/ranges"
}
],
"affected_versions": []
}
],
"severity": "high",
"structured": {
"id": "CVE-2026-53402",
"aliases": [
"CVE-2026-53402"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"type": "GIT",
"events": [
{
"introduced": "868749a7456dc48e93887a8474194e2ee6d6c21f"
},
{
"fixed": "cb016bcb40c81e7b19c4ae6143babb366dae8e20"
}
]
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"type": "GIT",
"events": [
{
"introduced": "ebd6f886aa2447fcfcdce5450c9e1028e1d681bb"
},
{
"fixed": "ac562193c36696513ae196171892e9338475c4bc"
}
]
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"type": "GIT",
"events": [
{
"introduced": "a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24"
},
{
"fixed": "3618a4c5b2591cfa83efe74f5b18c2d02b35c3f5"
},
{
"fixed": "a7a526fbc847f07ad3a503c7382189be5ab68574"
},
{
"fixed": "b5bb2c696e140c399cb874def2feedf61dee27d6"
},
{
"fixed": "076b1aa65f77a49bce5a48a4a55a397cfcafa2b8"
},
{
"fixed": "39815715cbcfabb16fc8c5f4a23deeda20f5df62"
},
{
"fixed": "8fdc8c2057eea08d40ce2c8eed41ff9e451c65c2"
}
]
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"type": "GIT",
"events": [
{
"introduced": "5.10.249"
},
{
"fixed": "5.10.261"
}
]
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"type": "GIT",
"events": [
{
"introduced": "5.15.64"
},
{
"fixed": "5.15.212"
}
]
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"type": "GIT",
"events": [
{
"introduced": "5.19.6"
},
{
"fixed": "5.20"
}
]
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"type": "GIT",
"events": [
{
"introduced": "f08ccb792d3eaf1dc62d8cbf6a30d6522329f660"
}
]
}
],
"versions": [
"v5.10.260",
"v5.10.259",
"v5.10.258",
"v5.10.257",
"v5.10.256",
"v5.10.255",
"v5.10.254",
"v5.10.253",
"v5.10.252",
"v5.10.251",
"v5.10.250",
"v5.10.249",
"v5.15.211",
"v5.15.210",
"v5.15.209",
"v5.15.208",
"v5.15.207",
"v5.15.206",
"v5.15.205",
"v5.15.204",
"v5.15.203",
"v5.15.202",
"v5.15.201",
"v5.15.200",
"v5.15.199",
"v5.15.198",
"v5.15.197",
"v5.15.196",
"v5.15.195",
"v5.15.194",
"v5.15.193",
"v5.15.192",
"v5.15.191",
"v5.15.190",
"v5.15.189",
"v5.15.188",
"v5.15.187",
"v5.15.186",
"v5.15.185",
"v5.15.184",
"v5.15.183",
"v5.15.182",
"v5.15.181",
"v5.15.180",
"v5.15.179",
"v5.15.178",
"v5.15.177",
"v5.15.176",
"v5.15.175",
"v5.15.174",
"v5.15.173",
"v5.15.172",
"v5.15.171",
"v5.15.170",
"v5.15.169",
"v5.15.168",
"v5.15.167",
"v5.15.166",
"v5.15.165",
"v5.15.164",
"v5.15.163",
"v5.15.162",
"v5.15.161",
"v5.15.160",
"v5.15.159",
"v5.15.158",
"v5.15.157",
"v5.15.156",
"v5.15.155",
"v5.15.154",
"v5.15.153",
"v5.15.152",
"v5.15.151",
"v5.15.150",
"v5.15.149",
"v5.15.148",
"v5.15.147",
"v5.15.146",
"v5.15.145",
"v5.15.144",
"v5.15.143",
"v5.15.142",
"v5.15.141",
"v5.15.140",
"v5.15.139",
"v5.15.138",
"v5.15.137",
"v5.15.136",
"v5.15.135",
"v5.15.134",
"v5.15.133",
"v5.15.132",
"v5.15.131",
"v5.15.130",
"v5.15.129",
"v5.15.128",
"v5.15.127",
"v5.15.126",
"v5.15.125",
"v5.15.124",
"v5.15.123",
"v5.15.122",
"v5.15.121",
"v5.15.120",
"v5.15.119",
"v5.15.118",
"v5.15.117",
"v5.15.116",
"v5.15.115",
"v5.15.114",
"v5.15.113",
"v5.15.112",
"v5.15.111",
"v5.15.110",
"v5.15.109",
"v5.15.108",
"v5.15.107",
"v5.15.106",
"v5.15.105",
"v5.15.104",
"v5.15.103",
"v5.15.102",
"v5.15.101",
"v5.15.100",
"v5.15.99",
"v5.15.98",
"v5.15.97",
"v5.15.96",
"v5.15.95",
"v5.15.94",
"v5.15.93",
"v5.15.92",
"v5.15.91",
"v5.15.90",
"v5.15.89",
"v5.15.88",
"v5.15.87",
"v5.15.86",
"v5.15.85",
"v5.15.84",
"v5.15.83",
"v5.15.82",
"v5.15.81",
"v5.15.80",
"v5.15.79",
"v5.15.78",
"v5.15.77",
"v5.15.76",
"v5.15.75",
"v5.15.74",
"v5.15.73",
"v5.15.72",
"v5.15.71",
"v5.15.70",
"v5.15.69",
"v5.15.68",
"v5.15.67",
"v5.15.66",
"v5.15.65",
"v5.15.64",
"v5.19.17",
"v5.19.16",
"v5.19.15",
"v5.19.14",
"v5.19.13",
"v5.19.12",
"v5.19.11",
"v5.19.10",
"v5.19.9",
"v5.19.8",
"v5.19.7",
"v5.19.6"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-53402.json"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "5.10.261"
}
]
},
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "5.11.0"
},
{
"fixed": "5.15.212"
}
]
},
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "5.16.0"
},
{
"fixed": "6.1.178"
}
]
},
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "6.0.0"
},
{
"fixed": "6.6.145"
}
]
},
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "6.2.0"
},
{
"fixed": "6.12.96"
}
]
},
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "6.7.0"
},
{
"fixed": "6.18.39"
}
]
},
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "6.13.0"
},
{
"fixed": "7.1.3"
}
]
}
],
"package": {
"name": "Kernel",
"ecosystem": "Linux"
},
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-53402.json"
}
}
],
"modified": "2026-10-28T02:30:45.823314065Z",
"provider": "osv",
"references": [
"https://git.kernel.org/stable/c/076b1aa65f77a49bce5a48a4a55a397cfcafa2b8",
"https://git.kernel.org/stable/c/3618a4c5b2591cfa83efe74f5b18c2d02b35c3f5",
"https://git.kernel.org/stable/c/39815715cbcfabb16fc8c5f4a23deeda20f5df62",
"https://git.kernel.org/stable/c/8fdc8c2057eea08d40ce2c8eed41ff9e451c65c2",
"https://git.kernel.org/stable/c/a7a526fbc847f07ad3a503c7382189be5ab68574",
"https://git.kernel.org/stable/c/ac562193c36696513ae196171892e9338475c4bc",
"https://git.kernel.org/stable/c/b5bb2c696e140c399cb874def2feedf61dee27d6",
"https://git.kernel.org/stable/c/cb016bcb40c81e7b19c4ae6143babb366dae8e20",
"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53402.json",
"https://nvd.nist.gov/vuln/detail/CVE-2026-53402",
"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
],
"provider_metadata": {
"cna_assigner": "Linux",
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53402.json"
}
},
"related_cves": [
{
"value": "CVE-2026-53402",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 513947,
"published_at": "2026-07-19T12:02:01.795+00:00"
}