{"cve":"CVE-2026-80578","nvd":{"published":"2026-08-26T15:17:13.880","modified":"2026-10-16T20:18:01.013","status":"Received","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nfbdev: core: Fix pointer desynchronization in fb_io_read()\n\nIn fb_io_read(), if copy_to_user() performs a partial copy (e.g., due to\na faulty user buffer), the loop adjusts the chunk size 'c' and updates\nthe remaining 'count'. However, the hardware 'src' pointer has already\nbeen eagerly advanced by the original chunk size.\n\nIf the loop is allowed to continue, the read will resume from an\nincorrect, over-advanced offset. Since the remaining 'count' was only\ndecremented by the successful bytes, this desynchronization causes the\nnext iterations to execute more hardware reads than originally bounded,\neventually leading to out-of-bounds I/O reads.\n\nFix this by breaking out of the loop immediately upon a partial\ncopy_to_user(). A partial copy indicates a faulty user buffer, making\nsubsequent read attempts futile. Breaking out ensures we return the\nnumber of successfully read bytes without risking out-of-bounds hardware\naccesses in subsequent mismatched iterations.","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:L/A:H","score":7.3},"cwes":[],"references":["https://git.kernel.org/stable/c/42a6d8126c194133eafab2b0fd5c8668ebfcba5b","https://git.kernel.org/stable/c/42bc07b4e5a3c8a02a433388f562a8f46d093e11","https://git.kernel.org/stable/c/7110b7b794a2aac2c5cf8eb06ebf2af724c74d50","https://git.kernel.org/stable/c/7ff87a01ae3a8cd0208f7499386998223a8b5dba","https://git.kernel.org/stable/c/81cc73be40c6f028f1ee3f438ace46afe666dbae"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:50:17.453294893+00:00"},"epss":{"cve":"CVE-2026-80578","score":0.00117,"percentile":0.01635,"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."]}