platform/x86: panasonic-laptop: Fix sentinel write past pcc->sinf[]
In the Linux kernel, the following vulnerability has been resolved: platform/x86: panasonic-laptop: Fix sentinel write past pcc->sinf[] acpi_pcc_retrieve_biosdata() rejects SINF packages only when pcc->num_sifr is strictly less than hkey->package.count, then unconditionally writes a trailing sentinel at pcc->sinf[hkey->package.count]. But pcc->sinf[] is allocated with exactly pcc->num_sifr elements (valid indices 0..num_sifr-1), so that write needs num_sifr strictly greater than package.count to stay in bounds -- num_sifr == package.count passes the existing check but still overflows by one element. This is exactly the case probe()'s existing num_sifr++ workaround ("Some DSDT-s have an off-by-one bug where the SINF package count is one higher than the SQTY reported value") is written to accommodate: when a DSDT's SINF package count equals SQTY+1, the workaround makes num_sifr equal to package.count, which is precisely the boundary that overflows here. Found via UBSan (array-index-out-of-bounds) on hardware where HKEY.SQTY returns 37 and HKEY.SINF()'s package has 38 elements: num_sifr becomes 38 after the += 1 workaround, the loop correctly fills indices 0..37, and the sentinel write then targets index 38, one past the end -- a silent 4-byte heap overflow on kernels without CONFIG_UBSAN. Tightening the rejection check to num_sifr <= package.count would avoid the overflow but breaks probe() entirely on exactly this hardware, since num_sifr == package.count is the case the off-b
CVE-2026-89436
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-2026-89436
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": "a3d0dbd18ce908292607bb6cf37c978ece8a33d4",
"lessThan": "a93df956ee4d903735b6d395362c839cb1dc07e3",
"versionType": "git"
},
{
"status": "affected",
"version": "a3d0dbd18ce908292607bb6cf37c978ece8a33d4",
"lessThan": "329f10d8be193bf36af124e00b9dd6644cd71724",
"versionType": "git"
}
],
"programFiles": [
"drivers/platform/x86/panasonic-laptop.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": "7.2.4",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"drivers/platform/x86/panasonic-laptop.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-89436
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #34973 · Revision 1
- Added to Heist Feed
- Publisher date