{"id":"CVE-2026-90203","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-90203","summary":"Squashfs: check block offset is not negative","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nSquashfs: check block offset is not negative\n\nIf a negative offset is read off disk (for example the offset into the\ndecompressed fragment block), this will cause squashfs_copy_data() to\nperform an out of bounds access.\n\nFix by checking if offset is negative, and returning 0.  This matches\nexisting behaviour where an offset beyond the block returns 0 bytes\ncopied.\n\nTo trigger this out of bounds access requires a crafted Squashfs\nfilesystem and CAP_SYS_ADMIN to mount it.  Unprivileged users will not be\nable to mount such a filesystem, but once mounted, an unprivileged user\ncan trigger the out of bounds access by reading the crafted file with the\nnegative offset.","published":"2026-09-17T16:07:20.180Z","modified":"2026-09-19T03:47:25.467386616Z","cvss":{"score":7.1,"severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Linux","name":"Kernel","fixedVersion":"5.10.270"}],"fix":null,"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/3d2f0cb66c909ea2312cdef465165bb9a3ba2d84"},{"type":"WEB","url":"https://git.kernel.org/stable/c/95dadf366c117dcdca78a570e6832071deab1ecd"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b169185d5c672b989985c6c2e38cafab2548ba88"},{"type":"WEB","url":"https://git.kernel.org/stable/c/bbb2218eb072b0a15dc063929200183bd23c2344"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c2a126fca820ae74872da28de68dc74d4595dc4b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d0a3729d464fcf516416a41cf304c0c92126ee03"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e300eb5002925b29be803d2661af07266cfa267e"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e4afd90bc7bf3dd477970c6c42bdd29ad3fda7fe"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90203.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-90203"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-19T03:47:25.467386616Z"}}