{"id":"CVE-2026-80550","title":"s390/vfio_ccw: Fix out of bounds check on CCW array","summary":"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…","severity":"high","cvss":7.9,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:L","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= 0a19e61e6d4c6192077ead760ba0a2d350987d4c < 0282fb1c4b638eecfe2cc558092c460911d8f7e2","Linux >= 0a19e61e6d4c6192077ead760ba0a2d350987d4c < 907adc667d902fafbdb2d740d57b55bd025dc4cd","Linux >= 0a19e61e6d4c6192077ead760ba0a2d350987d4c < f20be33d093ce7630c17ff7ed93caf7eaf8ac1a3","Linux >= 0a19e61e6d4c6192077ead760ba0a2d350987d4c < af3f80ca4c8b17f20f9e588def076288fdb49e65","Linux >= 0a19e61e6d4c6192077ead760ba0a2d350987d4c < 499a8a66b1598bfab97182aed15e0f1646074a3d","Linux >= 0a19e61e6d4c6192077ead760ba0a2d350987d4c < 4c2e1d359d7a2b82cdf3254e4e480af9417f99fb","Linux >= 0a19e61e6d4c6192077ead760ba0a2d350987d4c < d5d096cd9369e986d4e5153baa86b8b35c283e09","Linux >= 0a19e61e6d4c6192077ead760ba0a2d350987d4c < a005b7f1a491ffda61bff0fd0f6548f8986fb977","Linux 4.12"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-10-16T19:17:08.790140Z"},"published":"2026-08-26","updated":"2026-10-16","sourceUpdated":"2026-10-16T19:26:26.153Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-80550","references":[{"url":"https://git.kernel.org/stable/c/0282fb1c4b638eecfe2cc558092c460911d8f7e2"},{"url":"https://git.kernel.org/stable/c/907adc667d902fafbdb2d740d57b55bd025dc4cd"},{"url":"https://git.kernel.org/stable/c/f20be33d093ce7630c17ff7ed93caf7eaf8ac1a3"},{"url":"https://git.kernel.org/stable/c/af3f80ca4c8b17f20f9e588def076288fdb49e65"},{"url":"https://git.kernel.org/stable/c/499a8a66b1598bfab97182aed15e0f1646074a3d"},{"url":"https://git.kernel.org/stable/c/4c2e1d359d7a2b82cdf3254e4e480af9417f99fb"},{"url":"https://git.kernel.org/stable/c/d5d096cd9369e986d4e5153baa86b8b35c283e09"},{"url":"https://git.kernel.org/stable/c/a005b7f1a491ffda61bff0fd0f6548f8986fb977"}],"tags":["cve.org"],"epss":0.00181,"epssPercentile":0.0721,"ingestedAt":"2026-10-16T19:46:24.316Z","slug":"CVE-2026-80550","body":"## Overview\n\nIn 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.\n\n## Affected\n\n- `Linux >= 0a19e61e6d4c6192077ead760ba0a2d350987d4c < 0282fb1c4b638eecfe2cc558092c460911d8f7e2`\n- `Linux >= 0a19e61e6d4c6192077ead760ba0a2d350987d4c < 907adc667d902fafbdb2d740d57b55bd025dc4cd`\n- `Linux >= 0a19e61e6d4c6192077ead760ba0a2d350987d4c < f20be33d093ce7630c17ff7ed93caf7eaf8ac1a3`\n- `Linux >= 0a19e61e6d4c6192077ead760ba0a2d350987d4c < af3f80ca4c8b17f20f9e588def076288fdb49e65`\n- `Linux >= 0a19e61e6d4c6192077ead760ba0a2d350987d4c < 499a8a66b1598bfab97182aed15e0f1646074a3d`\n- `Linux >= 0a19e61e6d4c6192077ead760ba0a2d350987d4c < 4c2e1d359d7a2b82cdf3254e4e480af9417f99fb`\n- `Linux >= 0a19e61e6d4c6192077ead760ba0a2d350987d4c < d5d096cd9369e986d4e5153baa86b8b35c283e09`\n- `Linux >= 0a19e61e6d4c6192077ead760ba0a2d350987d4c < a005b7f1a491ffda61bff0fd0f6548f8986fb977`\n- `Linux 4.12`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":43.5,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}