{"id":"CVE-2025-39735","state":"PUBLISHED","title":"jfs: fix slab-out-of-bounds read in ea_get()","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.","publishedAt":"2025-04-18T07:01:36.453Z","updatedAt":"2026-08-05T12:04:55.584Z","severity":{"score":7.1,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"6e39b681d1eb16f408493bf5023788b57f68998c","status":"affected","lessThan":"3d6fd5b9c6acbc005e53d0211c7381f566babec1","versionType":"git"},{"version":"bbf3f1fd8a0ac7df1db36a9b9e923041a14369f2","status":"affected","lessThan":"50afcee7011155933d8d5e8832f52eeee018cfd3","versionType":"git"},{"version":"27a93c45e16ac25a0e2b5e5668e2d1beca56a478","status":"affected","lessThan":"78c9cbde8880ec02d864c166bcb4fe989ce1d95f","versionType":"git"},{"version":"9c356fc32a4480a2c0e537a05f2a8617633ddad0","status":"affected","lessThan":"46e2c031aa59ea65128991cbca474bd5c0c2ecdb","versionType":"git"},{"version":"9353cdf28d4c5c0ff19c5df7fbf81ea774de43a4","status":"affected","lessThan":"a8c31808925b11393a6601f534bb63bac5366bab","versionType":"git"},{"version":"8c505ebeed8045b488b2e60b516c752b851f8437","status":"affected","lessThan":"0beddc2a3f9b9cf7d8887973041e36c2d0fa3652","versionType":"git"},{"version":"d9f9d96136cba8fedd647d2c024342ce090133c2","status":"affected","lessThan":"16d3d36436492aa248b2d8045e75585ebcc2f34d","versionType":"git"},{"version":"d9f9d96136cba8fedd647d2c024342ce090133c2","status":"affected","lessThan":"5263822558a8a7c0d0248d5679c2dcf4d5cda61f","versionType":"git"},{"version":"d9f9d96136cba8fedd647d2c024342ce090133c2","status":"affected","lessThan":"fdf480da5837c23b146c4743c18de97202fcab37","versionType":"git"},{"version":"4ea25fa8747fb8b1e5a11d87b852023ecf7ae420","status":"affected","versionType":"git"},{"version":"676a787048aafd4d1b38a522b05a9cc77e1b0a33","status":"affected","versionType":"git"},{"version":"5.4.287","status":"affected","lessThan":"5.4.292","versionType":"semver"},{"version":"5.10.231","status":"affected","lessThan":"5.10.236","versionType":"semver"},{"version":"5.15.174","status":"affected","lessThan":"5.15.180","versionType":"semver"},{"version":"6.1.120","status":"affected","lessThan":"6.1.134","versionType":"semver"},{"version":"6.6.64","status":"affected","lessThan":"6.6.87","versionType":"semver"},{"version":"6.12.2","status":"affected","lessThan":"6.12.23","versionType":"semver"},{"version":"4.19.325","status":"affected","lessThan":"4.20","versionType":"semver"},{"version":"6.11.11","status":"affected","lessThan":"6.12","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/jfs/xattr.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.13","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.13","versionType":"semver"},{"version":"5.4.292","status":"unaffected","lessThanOrEqual":"5.4.*","versionType":"semver"},{"version":"5.10.236","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.180","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.134","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.87","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.23","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.13.11","status":"unaffected","lessThanOrEqual":"6.13.*","versionType":"semver"},{"version":"6.14.2","status":"unaffected","lessThanOrEqual":"6.14.*","versionType":"semver"},{"version":"6.15","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/jfs/xattr.c"]}],"references":["https://git.kernel.org/stable/c/3d6fd5b9c6acbc005e53d0211c7381f566babec1","https://git.kernel.org/stable/c/50afcee7011155933d8d5e8832f52eeee018cfd3","https://git.kernel.org/stable/c/78c9cbde8880ec02d864c166bcb4fe989ce1d95f","https://git.kernel.org/stable/c/46e2c031aa59ea65128991cbca474bd5c0c2ecdb","https://git.kernel.org/stable/c/a8c31808925b11393a6601f534bb63bac5366bab","https://git.kernel.org/stable/c/0beddc2a3f9b9cf7d8887973041e36c2d0fa3652","https://git.kernel.org/stable/c/16d3d36436492aa248b2d8045e75585ebcc2f34d","https://git.kernel.org/stable/c/5263822558a8a7c0d0248d5679c2dcf4d5cda61f","https://git.kernel.org/stable/c/fdf480da5837c23b146c4743c18de97202fcab37","https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html","https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html"],"weaknesses":["CWE-125"],"ingestedAt":"2026-10-29T20:09:09.358Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2025/39xxx/CVE-2025-39735.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-39735","state":"PUBLISHED","datePublished":"2025-04-18T07:01:36.453Z","dateUpdated":"2026-08-05T12:04:55.584Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2025-04-16T07:20:57.119Z"},"containers":{"cna":{"title":"jfs: fix slab-out-of-bounds read in ea_get()","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"6e39b681d1eb16f408493bf5023788b57f68998c","status":"affected","lessThan":"3d6fd5b9c6acbc005e53d0211c7381f566babec1","versionType":"git"},{"version":"bbf3f1fd8a0ac7df1db36a9b9e923041a14369f2","status":"affected","lessThan":"50afcee7011155933d8d5e8832f52eeee018cfd3","versionType":"git"},{"version":"27a93c45e16ac25a0e2b5e5668e2d1beca56a478","status":"affected","lessThan":"78c9cbde8880ec02d864c166bcb4fe989ce1d95f","versionType":"git"},{"version":"9c356fc32a4480a2c0e537a05f2a8617633ddad0","status":"affected","lessThan":"46e2c031aa59ea65128991cbca474bd5c0c2ecdb","versionType":"git"},{"version":"9353cdf28d4c5c0ff19c5df7fbf81ea774de43a4","status":"affected","lessThan":"a8c31808925b11393a6601f534bb63bac5366bab","versionType":"git"},{"version":"8c505ebeed8045b488b2e60b516c752b851f8437","status":"affected","lessThan":"0beddc2a3f9b9cf7d8887973041e36c2d0fa3652","versionType":"git"},{"version":"d9f9d96136cba8fedd647d2c024342ce090133c2","status":"affected","lessThan":"16d3d36436492aa248b2d8045e75585ebcc2f34d","versionType":"git"},{"version":"d9f9d96136cba8fedd647d2c024342ce090133c2","status":"affected","lessThan":"5263822558a8a7c0d0248d5679c2dcf4d5cda61f","versionType":"git"},{"version":"d9f9d96136cba8fedd647d2c024342ce090133c2","status":"affected","lessThan":"fdf480da5837c23b146c4743c18de97202fcab37","versionType":"git"},{"version":"4ea25fa8747fb8b1e5a11d87b852023ecf7ae420","status":"affected","versionType":"git"},{"version":"676a787048aafd4d1b38a522b05a9cc77e1b0a33","status":"affected","versionType":"git"},{"version":"5.4.287","status":"affected","lessThan":"5.4.292","versionType":"semver"},{"version":"5.10.231","status":"affected","lessThan":"5.10.236","versionType":"semver"},{"version":"5.15.174","status":"affected","lessThan":"5.15.180","versionType":"semver"},{"version":"6.1.120","status":"affected","lessThan":"6.1.134","versionType":"semver"},{"version":"6.6.64","status":"affected","lessThan":"6.6.87","versionType":"semver"},{"version":"6.12.2","status":"affected","lessThan":"6.12.23","versionType":"semver"},{"version":"4.19.325","status":"affected","lessThan":"4.20","versionType":"semver"},{"version":"6.11.11","status":"affected","lessThan":"6.12","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/jfs/xattr.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.13","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.13","versionType":"semver"},{"version":"5.4.292","status":"unaffected","lessThanOrEqual":"5.4.*","versionType":"semver"},{"version":"5.10.236","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.180","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.134","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.87","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.23","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.13.11","status":"unaffected","lessThanOrEqual":"6.13.*","versionType":"semver"},{"version":"6.14.2","status":"unaffected","lessThanOrEqual":"6.14.*","versionType":"semver"},{"version":"6.15","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/jfs/xattr.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/3d6fd5b9c6acbc005e53d0211c7381f566babec1"},{"url":"https://git.kernel.org/stable/c/50afcee7011155933d8d5e8832f52eeee018cfd3"},{"url":"https://git.kernel.org/stable/c/78c9cbde8880ec02d864c166bcb4fe989ce1d95f"},{"url":"https://git.kernel.org/stable/c/46e2c031aa59ea65128991cbca474bd5c0c2ecdb"},{"url":"https://git.kernel.org/stable/c/a8c31808925b11393a6601f534bb63bac5366bab"},{"url":"https://git.kernel.org/stable/c/0beddc2a3f9b9cf7d8887973041e36c2d0fa3652"},{"url":"https://git.kernel.org/stable/c/16d3d36436492aa248b2d8045e75585ebcc2f34d"},{"url":"https://git.kernel.org/stable/c/5263822558a8a7c0d0248d5679c2dcf4d5cda61f"},{"url":"https://git.kernel.org/stable/c/fdf480da5837c23b146c4743c18de97202fcab37"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","baseScore":7.1,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - JFS is a block-device filesystem (FS_REQUIRES_DEV); the malicious `size` field must arrive via a locally attached/mounted volume, and the trigger is a local syscall (listxattr/getxattr/setxattr) or an ACL lookup on a file in that volume. There is no network-facing path to `ea_get()`.\nAC:L - The attacker fully and deterministically controls the on-disk `jfs_ea_list.size` field; setting it above INT_MAX guarantees the negative clamp on every access, with no race to win and no dependence on memory layout the attacker cannot influence.\nPR:L - `ea_get()` runs before any permission or name check in `__jfs_getxattr`/`jfs_listxattr`, and is reached from `jfs_get_acl()` during ordinary permission checks, so an unprivileged user with read/search access to the mounted crafted volume triggers it; in the auto-mount/kiosk scenario the equivalent unprivileged-attacker framing PR:N/UI:R yields the same score.\nUI:N - Once the crafted volume is mounted (attacker-inserted removable media auto-mounted by udisks2, or an admin-mounted untrusted image), no victim action is required — the attacker's own `listxattr()`/`getxattr()` call, or even a path-traversal ACL lookup, reaches the bug directly.\nS:U - The out-of-bounds reads and the resulting oops are confined to the kernel's own security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - The corrupted length drives an effectively unbounded walk past (and before) the ea buffer, hex-dumping 16 bytes of adjacent kernel heap memory per iteration — together with kernel addresses — into the kernel log; this is a large-scale kernel memory disclosure, not a small bounded read.\nI:N - The defect is read-only: `hex_dump_to_buffer()` clamps its per-line length to rowsize and bounds-checks `linebuf` at every byte, so no out-of-bounds write or memory corruption occurs and no control-flow primitive is produced.\nA:H - The loop performs billions of `printk` iterations (console livelock, soft lockup, RCU stalls, log flooding) and inevitably dereferences an unmapped kernel address, producing a KASAN report or page-fault oops/panic."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T12:04:55.584Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.4.287","versionEndExcluding":"5.4.292"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10.231","versionEndExcluding":"5.10.236"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15.174","versionEndExcluding":"5.15.180"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1.120","versionEndExcluding":"6.1.134"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6.64","versionEndExcluding":"6.6.87"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12.2","versionEndExcluding":"6.12.23"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.13","versionEndExcluding":"6.13.11"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.13","versionEndExcluding":"6.14.2"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.13","versionEndExcluding":"6.15"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.19.325"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.11.11"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":7.1,"attackVector":"LOCAL","baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","integrityImpact":"NONE","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"HIGH","privilegesRequired":"LOW","confidentialityImpact":"HIGH"}},{"other":{"type":"ssvc","content":{"timestamp":"2025-10-01T16:13:35.286674Z","id":"CVE-2025-39735","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-125","type":"CWE","lang":"en","description":"CWE-125 Out-of-bounds Read"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2025-10-01T16:13:38.835Z"}},{"title":"CVE Program Container","references":[{"url":"https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html"},{"url":"https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html"}],"providerMetadata":{"shortName":"CVE","orgId":"af854a3a-2127-422b-91ae-364da2661108","dateUpdated":"2025-11-03T19:58:46.112Z"}}]}}}