{"cve":"CVE-2026-89436","nvd":{"published":"2026-09-11T20:19:23.847","modified":"2026-10-19T09:17:35.440","status":"Received","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nplatform/x86: panasonic-laptop: Fix sentinel write past pcc->sinf[]\n\nacpi_pcc_retrieve_biosdata() rejects SINF packages only when\npcc->num_sifr is strictly less than hkey->package.count, then\nunconditionally writes a trailing sentinel at\npcc->sinf[hkey->package.count]. But pcc->sinf[] is allocated with\nexactly pcc->num_sifr elements (valid indices 0..num_sifr-1), so that\nwrite needs num_sifr strictly greater than package.count to stay in\nbounds -- num_sifr == package.count passes the existing check but\nstill overflows by one element.\n\nThis is exactly the case probe()'s existing num_sifr++ workaround\n(\"Some DSDT-s have an off-by-one bug where the SINF package count is\none higher than the SQTY reported value\") is written to accommodate:\nwhen a DSDT's SINF package count equals SQTY+1, the workaround makes\nnum_sifr equal to package.count, which is precisely the boundary that\noverflows here. Found via UBSan (array-index-out-of-bounds) on\nhardware where HKEY.SQTY returns 37 and HKEY.SINF()'s package has 38\nelements: num_sifr becomes 38 after the += 1 workaround, the loop\ncorrectly fills indices 0..37, and the sentinel write then targets\nindex 38, one past the end -- a silent 4-byte heap overflow on kernels\nwithout CONFIG_UBSAN.\n\nTightening the rejection check to num_sifr <= package.count would\navoid the overflow but breaks probe() entirely on exactly this\nhardware, since num_sifr == package.count is the case the off-by-one\nworkaround exists to support. Nothing else in the driver reads this\nsentinel value back, so simply skip the write when there is no room\nfor it instead.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8},"cwes":[],"references":["https://git.kernel.org/stable/c/329f10d8be193bf36af124e00b9dd6644cd71724","https://git.kernel.org/stable/c/a93df956ee4d903735b6d395362c839cb1dc07e3"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:53:43.293028046+00:00"},"epss":{"cve":"CVE-2026-89436","score":0.00178,"percentile":0.0736,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}