{"cve":"CVE-2026-80550","nvd":{"published":"2026-08-26T15:17:09.477","modified":"2026-10-16T20:17:59.223","status":"Received","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ns390/vfio_ccw: Fix out of bounds check on CCW array\n\nThe routine ccwchain_calc_length() counts the number of channel\ncommand words (CCWs) that are chained together in a single channel\nprogram, and rejects anything larger than CCWCHAIN_LEN_MAX (256) CCWs.\n\nThe loop itself is \"do..while (count < 257)\", and while the logic in\nis_cpa_within_range() correctly adjusts between the 0-index array of\nCCWs and the count of CCWs starting at 1, this means it would look\nat a possible 257th CCW before ending the loop and (correctly)\nreturning an error.\n\nFix this by restructuring the loop to break as soon as 256 CCWs\n(thus indexes 0-255) are examined, without looking at memory\noutside the range.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:L","score":7.9},"cwes":[],"references":["https://git.kernel.org/stable/c/0282fb1c4b638eecfe2cc558092c460911d8f7e2","https://git.kernel.org/stable/c/499a8a66b1598bfab97182aed15e0f1646074a3d","https://git.kernel.org/stable/c/4c2e1d359d7a2b82cdf3254e4e480af9417f99fb","https://git.kernel.org/stable/c/907adc667d902fafbdb2d740d57b55bd025dc4cd","https://git.kernel.org/stable/c/a005b7f1a491ffda61bff0fd0f6548f8986fb977"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:50:17.453294893+00:00"},"epss":{"cve":"CVE-2026-80550","score":0.00181,"percentile":0.07651,"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."]}