CVE-2026-89436

CVE CVE-2026-89436EUVD EUVD-2026-76342Published 2026-09-11T19:43:06.000ZLast changed 2026-09-13T06:29:20.000ZCVSS 7.8

What the advisory describes

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-by-one workaround exists to support. Nothing else in the driver reads this sentinel value back, so simply skip the write when there is no room for it instead.

Source: EUVD (ENISA), in the words of the advisory.

Products the advisory names

These come from the advisory itself, not from any check we performed.

• Linux — Linux patch: 0; a3d0dbd18ce908292607bb6cf37c978ece8a33d4 <a93df956ee4d903735b6d395362c839cb1dc07e3; patch: 7.3-rc1; patch: 7.2.4; 7.2; a3d0dbd18ce908292607bb6cf37c978ece8a33d4 <329f10d8be193bf36af124e00b9dd6644cd71724

The versions shown are the advisory's own. Patchlage compares no version numbers and derives no judgement from them — which version is installed is something a person has to look up.

Carried in the product catalogue

An estate covering these products can be recorded in Patchlage. An advisory about them appears in the next morning's situation report.

• Linux — Linux

Patchlage reports hits and suspected hits. About everything else this system says nothing — neither this page nor the situation report ever claims that an estate is safe.