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.
CVE-2026-53402
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-2026-53402
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": "868749a7456dc48e93887a8474194e2ee6d6c21f",
"lessThan": "cb016bcb40c81e7b19c4ae6143babb366dae8e20",
"versionType": "git"
},
{
"status": "affected",
"version": "ebd6f886aa2447fcfcdce5450c9e1028e1d681bb",
"lessThan": "ac562193c36696513ae196171892e9338475c4bc",
"versionType": "git"
},
{
"status": "affected",
"version": "a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24",
"lessThan": "3618a4c5b2591cfa83efe74f5b18c2d02b35c3f5",
"versionType": "git"
},
{
"status": "affected",
"version": "a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24",
"lessThan": "a7a526fbc847f07ad3a503c7382189be5ab68574",
"versionType": "git"
},
{
"status": "affected",
"version": "a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24",
"lessThan": "b5bb2c696e140c399cb874def2feedf61dee27d6",
"versionType": "git"
},
{
"status": "affected",
"version": "a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24",
"lessThan": "076b1aa65f77a49bce5a48a4a55a397cfcafa2b8",
"versionType": "git"
},
{
"status": "affected",
"version": "a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24",
"lessThan": "39815715cbcfabb16fc8c5f4a23deeda20f5df62",
"versionType": "git"
},
{
"status": "affected",
"version": "a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24",
"lessThan": "8fdc8c2057eea08d40ce2c8eed41ff9e451c65c2",
"versionType": "git"
},
{
"status": "affected",
"version": "f08ccb792d3eaf1dc62d8cbf6a30d6522329f660",
"versionType": "git"
},
{
"status": "affected",
"version": "5.10.249",
"lessThan": "5.10.261",
"versionType": "semver"
},
{
"status": "affected",
"version": "5.15.64",
"lessThan": "5.15.212",
"versionType": "semver"
},
{
"status": "affected",
"version": "5.19.6",
"lessThan": "5.20",
"versionType": "semver"
}
],
"programFiles": [
"drivers/video/fbdev/core/fbcon.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.0"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.0",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.261",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.212",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.178",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.145",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.96",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.39",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.1.3",
"versionType": "semver",
"lessThanOrEqual": "7.1.*"
},
{
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"drivers/video/fbdev/core/fbcon.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-53402
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #40827 · Revision 1
- Added to Heist Feed
- Publisher date