{"cve":"CVE-2026-98636","nvd":{"published":"2026-10-18T16:17:16.700","modified":"2026-10-19T10:19:27.837","status":"Received","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsquashfs: Add dictionary size range check to prevent shift-out-of-bounds\n\nWhen an abnormal SquashFS image (COMP_OPTS flag is 1 but dictionary size\nis 0) is mounted, and performs shift operations using dictionarysize, the\nshift exponent is -1, causing a shift-out-of-bounds.\n\nDetail as below:\nsquashfs_comp_opts(msblk, buffer, length)\n  squashfs_xz_comp_opts()\n    if (comp_opts)\n      n = ffs(opts->dict_size) - 1;<----opts->dict_size=0, n=-1\n      if (opts->dict_size != (1 << n) && opts->dict_size !=\n\t  \t(1 << n) + (1 << (n + 1))) <----shift-out-of-bounds\n\nFix it by adding a dictionary size range check before the shift operation.","cvss_v4":null,"cvss_v3":null,"cwes":[],"references":["https://git.kernel.org/stable/c/0cb85377daaefb4ce5ce72975f2deb27ee0e0cad","https://git.kernel.org/stable/c/1f7745fb3580152ca902ef181b605f33cabfb1d0","https://git.kernel.org/stable/c/7a1c293e7aa17f1afaee0684e0e931fe23a5a6b1","https://git.kernel.org/stable/c/88c673a0bd233df44ca0020da82f4fd3876de27a","https://git.kernel.org/stable/c/9d9c5c218ea356a1d88765214ad2919605280ab1"],"products":[],"source":"nvd","synced_at":"2026-10-19T23:00:53.604569364+00:00"},"epss":{"cve":"CVE-2026-98636","score":0.00177,"percentile":0.07178,"date":"2026-10-26"},"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."]}