{"id":"CVE-2022-49418","state":"PUBLISHED","title":"NFSv4: Fix free of uninitialized nfs4_label on referral lookup.","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nNFSv4: Fix free of uninitialized nfs4_label on referral lookup.\n\nSend along the already-allocated fattr along with nfs4_fs_locations, and\ndrop the memcpy of fattr.  We end up growing two more allocations, but this\nfixes up a crash as:\n\nPID: 790    TASK: ffff88811b43c000  CPU: 0   COMMAND: \"ls\"\n #0 [ffffc90000857920] panic at ffffffff81b9bfde\n #1 [ffffc900008579c0] do_trap at ffffffff81023a9b\n #2 [ffffc90000857a10] do_error_trap at ffffffff81023b78\n #3 [ffffc90000857a58] exc_stack_segment at ffffffff81be1f45\n #4 [ffffc90000857a80] asm_exc_stack_segment at ffffffff81c009de\n #5 [ffffc90000857b08] nfs_lookup at ffffffffa0302322 [nfs]\n #6 [ffffc90000857b70] __lookup_slow at ffffffff813a4a5f\n #7 [ffffc90000857c60] walk_component at ffffffff813a86c4\n #8 [ffffc90000857cb8] path_lookupat at ffffffff813a9553\n #9 [ffffc90000857cf0] filename_lookup at ffffffff813ab86b","publishedAt":"2025-02-26T02:12:43.359Z","updatedAt":"2026-08-05T08:55:09.630Z","severity":{"score":9.8,"label":"Critical","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"9558a007dbc383d48e7f5a123d0b5ff656c71068","status":"affected","lessThan":"6015292653d95ba9f72906e2b65e536aa5807d64","versionType":"git"},{"version":"9558a007dbc383d48e7f5a123d0b5ff656c71068","status":"affected","lessThan":"c3ed222745d9ad7b69299b349a64ba533c64a34f","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/nfs/nfs4namespace.c","fs/nfs/nfs4proc.c","fs/nfs/nfs4state.c","fs/nfs/nfs4xdr.c","include/linux/nfs_xdr.h"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.16","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.16","versionType":"semver"},{"version":"5.18.3","status":"unaffected","lessThanOrEqual":"5.18.*","versionType":"semver"},{"version":"5.19","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/nfs/nfs4namespace.c","fs/nfs/nfs4proc.c","fs/nfs/nfs4state.c","fs/nfs/nfs4xdr.c","include/linux/nfs_xdr.h"]}],"references":["https://git.kernel.org/stable/c/6015292653d95ba9f72906e2b65e536aa5807d64","https://git.kernel.org/stable/c/c3ed222745d9ad7b69299b349a64ba533c64a34f"],"weaknesses":[],"ingestedAt":"2026-10-29T20:05:26.763Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2022/49xxx/CVE-2022-49418.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2022-49418","state":"PUBLISHED","datePublished":"2025-02-26T02:12:43.359Z","dateUpdated":"2026-08-05T08:55:09.630Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2025-02-26T02:08:31.568Z"},"containers":{"cna":{"title":"NFSv4: Fix free of uninitialized nfs4_label on referral lookup.","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nNFSv4: Fix free of uninitialized nfs4_label on referral lookup.\n\nSend along the already-allocated fattr along with nfs4_fs_locations, and\ndrop the memcpy of fattr.  We end up growing two more allocations, but this\nfixes up a crash as:\n\nPID: 790    TASK: ffff88811b43c000  CPU: 0   COMMAND: \"ls\"\n #0 [ffffc90000857920] panic at ffffffff81b9bfde\n #1 [ffffc900008579c0] do_trap at ffffffff81023a9b\n #2 [ffffc90000857a10] do_error_trap at ffffffff81023b78\n #3 [ffffc90000857a58] exc_stack_segment at ffffffff81be1f45\n #4 [ffffc90000857a80] asm_exc_stack_segment at ffffffff81c009de\n #5 [ffffc90000857b08] nfs_lookup at ffffffffa0302322 [nfs]\n #6 [ffffc90000857b70] __lookup_slow at ffffffff813a4a5f\n #7 [ffffc90000857c60] walk_component at ffffffff813a86c4\n #8 [ffffc90000857cb8] path_lookupat at ffffffff813a9553\n #9 [ffffc90000857cf0] filename_lookup at ffffffff813ab86b"}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"9558a007dbc383d48e7f5a123d0b5ff656c71068","status":"affected","lessThan":"6015292653d95ba9f72906e2b65e536aa5807d64","versionType":"git"},{"version":"9558a007dbc383d48e7f5a123d0b5ff656c71068","status":"affected","lessThan":"c3ed222745d9ad7b69299b349a64ba533c64a34f","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/nfs/nfs4namespace.c","fs/nfs/nfs4proc.c","fs/nfs/nfs4state.c","fs/nfs/nfs4xdr.c","include/linux/nfs_xdr.h"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.16","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.16","versionType":"semver"},{"version":"5.18.3","status":"unaffected","lessThanOrEqual":"5.18.*","versionType":"semver"},{"version":"5.19","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/nfs/nfs4namespace.c","fs/nfs/nfs4proc.c","fs/nfs/nfs4state.c","fs/nfs/nfs4xdr.c","include/linux/nfs_xdr.h"]}],"references":[{"url":"https://git.kernel.org/stable/c/6015292653d95ba9f72906e2b65e536aa5807d64"},{"url":"https://git.kernel.org/stable/c/c3ed222745d9ad7b69299b349a64ba533c64a34f"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":9.8,"baseSeverity":"CRITICAL"},"scenarios":[{"lang":"en","value":"AV:N - The bug is in the NFSv4 client referral path (fs/nfs): a malicious or compromised NFS server drives it by returning NFS4ERR_MOVED on LOOKUP and a successful FS_LOCATIONS reply with a different fsid over the network.\nAC:L - The remote server fully controls when MOVED/referral replies are sent and can trigger the path deterministically; CONFIG_NFS_V4_SECURITY_LABEL defaults to y, so the uninitialized-label free is not gated on a rare config.\nPR:N - Exploitation is from the remote NFS peer (or on-path AUTH_SYS attacker) with no account or capability on the victim client; no client-side privileges are required beyond an existing NFSv4 mount relationship.\nUI:N - An already-mounted NFSv4 export plus ordinary client lookups/revalidations (or automount activity) is enough; the malicious server can wait for routine pathwalks without a distinct victim action at exploit time.\nS:U - The uninitialized free and resulting heap corruption stay in the client kernel address space within the same security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - memcpy replaces a valid fattr->label with uninitialized kmalloc garbage, then nfs4_label_free dereferences that pointer (kfree(label->label)/kfree(label)), yielding memory-corruption primitives that can disclose kernel memory when the freed object is reclaimed.\nI:H - Freeing an uninitialized nfs4_label pointer is an arbitrary/corrupt free suitable for heap manipulation and control-flow hijacking, consistent with treating this class of memory corruption as high integrity impact.\nA:H - The reported crash is a kernel panic/oops in nfs_lookup (exc_stack_segment) when the garbage label is freed, and the corruption is repeatable whenever the server returns a referral."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T08:55:09.630Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.16","versionEndExcluding":"5.18.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.16","versionEndExcluding":"5.19"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}