{"cve":"CVE-2025-39735","nvd":{"published":"2025-04-18T07:15:44.150","modified":"2026-06-17T09:18:22.470","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\njfs: fix slab-out-of-bounds read in ea_get()\n\nDuring the \"size_check\" label in ea_get(), the code checks if the extended\nattribute list (xattr) size matches ea_size. If not, it logs\n\"ea_get: invalid extended attribute\" and calls print_hex_dump().\n\nHere, EALIST_SIZE(ea_buf->xattr) returns 4110417968, which exceeds\nINT_MAX (2,147,483,647). Then ea_size is clamped:\n\n\tint size = clamp_t(int, ea_size, 0, EALIST_SIZE(ea_buf->xattr));\n\nAlthough clamp_t aims to bound ea_size between 0 and 4110417968, the upper\nlimit is treated as an int, causing an overflow above 2^31 - 1. This leads\n\"size\" to wrap around and become negative (-184549328).\n\nThe \"size\" is then passed to print_hex_dump() (called \"len\" in\nprint_hex_dump()), it is passed as type size_t (an unsigned\ntype), this is then stored inside a variable called\n\"int remaining\", which is then assigned to \"int linelen\" which\nis then passed to hex_dump_to_buffer(). In print_hex_dump()\nthe for loop, iterates through 0 to len-1, where len is\n18446744073525002176, calling hex_dump_to_buffer()\non each iteration:\n\n\tfor (i = 0; i < len; i += rowsize) {\n\t\tlinelen = min(remaining, rowsize);\n\t\tremaining -= rowsize;\n\n\t\thex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,\n\t\t\t\t   linebuf, sizeof(linebuf), ascii);\n\n\t\t...\n\t}\n\nThe expected stopping condition (i < len) is effectively broken\nsince len is corrupted and very large. This eventually leads to\nthe \"ptr+i\" being passed to hex_dump_to_buffer() to get closer\nto the end of the actual bounds of \"ptr\", eventually an out of\nbounds access is done in hex_dump_to_buffer() in the following\nfor loop:\n\n\tfor (j = 0; j < len; j++) {\n\t\t\tif (linebuflen < lx + 2)\n\t\t\t\tgoto overflow2;\n\t\t\tch = ptr[j];\n\t\t...\n\t}\n\nTo fix this we should validate \"EALIST_SIZE(ea_buf->xattr)\"\nbefore it is utilised.","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:N/A:H","score":7.1},"cwes":["CWE-125"],"references":["https://git.kernel.org/stable/c/0beddc2a3f9b9cf7d8887973041e36c2d0fa3652","https://git.kernel.org/stable/c/16d3d36436492aa248b2d8045e75585ebcc2f34d","https://git.kernel.org/stable/c/3d6fd5b9c6acbc005e53d0211c7381f566babec1","https://git.kernel.org/stable/c/46e2c031aa59ea65128991cbca474bd5c0c2ecdb","https://git.kernel.org/stable/c/50afcee7011155933d8d5e8832f52eeee018cfd3"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:01:11.054312287+00:00"},"epss":{"cve":"CVE-2025-39735","score":0.00296,"percentile":0.22312,"date":"2026-10-31"},"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."]}