{"cve":{"cve_id":"CVE-2021-47107","is_kev":false,"kev_date_added":null,"kev_vendor_project":null,"kev_product":null,"kev_vulnerability_name":null,"kev_short_description":null,"kev_required_action":null,"kev_due_date":null,"kev_known_ransomware":null,"kev_notes":null,"kev_cwes":null,"epss_score":0.00847,"epss_percentile":0.55056,"epss_as_of":"2026-08-28","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nNFSD: Fix READDIR buffer overflow\n\nIf a client sends a READDIR count argument that is too small (say,\nzero), then the buffer size calculation in the new init_dirlist\nhelper functions results in an underflow, allowing the XDR stream\nfunctions to write beyond the actual buffer.\n\nThis calculation has always been suspect. NFSD has never sanity-\nchecked the READDIR count argument, but the old entry encoders\nmanaged the problem correctly.\n\nWith the commits below, entry encoding changed, exposing the\nunderflow to the pointer arithmetic in xdr_reserve_space().\n\nModern NFS clients attempt to retrieve as much data as possible\nfor each READDIR request. Also, we have no unit tests that\nexercise the behavior of READDIR at the lower bound of @count\nvalues. Thus this case was missed during testing.","published_at":"2024-03-04T18:15:38.706000Z","last_modified_at":"2026-08-04T10:16:46.147000Z","cvss_v3_score":9.8,"cvss_v3_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cvss_v3_severity":"CRITICAL","cvss_v4_score":null,"cvss_v4_vector":null,"cvss_v4_severity":null,"ssvc_decision":null,"ssvc_exploitation":"none","ssvc_automatable":false,"ssvc_technical_impact":"partial","cwes":["CWE-120"],"nvd_references":["https://git.kernel.org/stable/c/9e291a6a28d32545ed2fd959a8165144d1724df1","https://git.kernel.org/stable/c/eabc0aab98e5218ceecd82069b0d6fdfff5ee885","https://git.kernel.org/stable/c/53b1119a6e5028b125f431a0116ba73510d82a72"],"vuln_status":"Modified","trending_score":null,"is_trending":false,"has_trended":false,"trended_number_one":false,"trending_peak_score":null,"trending_peak_rank":null,"started_trending_at":null,"trended_number_one_at":null,"summary_generated":null,"summary_generated_at":null,"summary_model":null,"created_at":"2026-06-24T00:09:39.878444Z","updated_at":"2026-08-05T01:36:34.895396Z"},"effective_severity":"CRITICAL","badges":[],"impact_analysis":[],"cvss_v3_decoded":{"version":"3.1","metrics":[{"metric":"AV","name":"Attack Vector","value":"N","value_label":"Network"},{"metric":"AC","name":"Attack Complexity","value":"L","value_label":"Low"},{"metric":"PR","name":"Privileges Required","value":"N","value_label":"None"},{"metric":"UI","name":"User Interaction","value":"N","value_label":"None"},{"metric":"S","name":"Scope","value":"U","value_label":"Unchanged"},{"metric":"C","name":"Confidentiality","value":"H","value_label":"High"},{"metric":"I","name":"Integrity","value":"H","value_label":"High"},{"metric":"A","name":"Availability","value":"H","value_label":"High"}]},"cvss_v4_decoded":{"version":null,"metrics":[]},"affected":[{"vendor_slug":"linux","vendor_name":"linux","product_slug":"linux","product_name":"Linux","version_start":"37aa5e64022243e721b8334122997881177a4cfc","version_start_inclusive":true,"version_end":"9e291a6a28d32545ed2fd959a8165144d1724df1","version_end_inclusive":false,"cpe23_uri":"cve5:linux:linux:37aa5e64022243e721b8334122997881177a4cfc:9e291a6a28d32545ed2fd959a8165144d1724df1"},{"vendor_slug":"linux","vendor_name":"linux","product_slug":"linux","product_name":"Linux","version_start":"7f87fc2d34d475225e78b7f5c4eabb121f4282b2","version_start_inclusive":true,"version_end":"eabc0aab98e5218ceecd82069b0d6fdfff5ee885","version_end_inclusive":false,"cpe23_uri":"cve5:linux:linux:7f87fc2d34d475225e78b7f5c4eabb121f4282b2:eabc0aab98e5218ceecd82069b0d6fdfff5ee885"},{"vendor_slug":"linux","vendor_name":"linux","product_slug":"linux","product_name":"Linux","version_start":"7f87fc2d34d475225e78b7f5c4eabb121f4282b2","version_start_inclusive":true,"version_end":"53b1119a6e5028b125f431a0116ba73510d82a72","version_end_inclusive":false,"cpe23_uri":"cve5:linux:linux:7f87fc2d34d475225e78b7f5c4eabb121f4282b2:53b1119a6e5028b125f431a0116ba73510d82a72"},{"vendor_slug":"linux","vendor_name":"linux","product_slug":"linux","product_name":"Linux","version_start":"5.13","version_start_inclusive":true,"version_end":"5.13","version_end_inclusive":true,"cpe23_uri":"cve5:linux:linux:5.13:5.13"},{"vendor_slug":"linux","vendor_name":"linux","product_slug":"linux","product_name":"Linux","version_start":"0","version_start_inclusive":true,"version_end":"5.13","version_end_inclusive":false,"cpe23_uri":"cve5:linux:linux:0:5.13"},{"vendor_slug":"linux","vendor_name":"linux","product_slug":"linux","product_name":"Linux","version_start":"5.15.12","version_start_inclusive":true,"version_end":"5.15.*","version_end_inclusive":true,"cpe23_uri":"cve5:linux:linux:5.15.12:5.15.*"},{"vendor_slug":"linux","vendor_name":"linux","product_slug":"linux","product_name":"Linux","version_start":"5.16","version_start_inclusive":true,"version_end":"*","version_end_inclusive":true,"cpe23_uri":"cve5:linux:linux:5.16:*"},{"vendor_slug":"linux","vendor_name":"linux","product_slug":"linux-kernel","product_name":"linux_kernel","version_start":"5.13","version_start_inclusive":true,"version_end":"5.15.12","version_end_inclusive":false,"cpe23_uri":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*"},{"vendor_slug":"linux","vendor_name":"linux","product_slug":"linux-kernel","product_name":"linux_kernel","version_start":"5.16","version_start_inclusive":true,"version_end":"5.16","version_end_inclusive":true,"cpe23_uri":"cpe:2.3:o:linux:linux_kernel:5.16:rc1:*:*:*:*:*:*"},{"vendor_slug":"linux","vendor_name":"linux","product_slug":"linux-kernel","product_name":"linux_kernel","version_start":"5.16","version_start_inclusive":true,"version_end":"5.16","version_end_inclusive":true,"cpe23_uri":"cpe:2.3:o:linux:linux_kernel:5.16:rc2:*:*:*:*:*:*"},{"vendor_slug":"linux","vendor_name":"linux","product_slug":"linux-kernel","product_name":"linux_kernel","version_start":"5.16","version_start_inclusive":true,"version_end":"5.16","version_end_inclusive":true,"cpe23_uri":"cpe:2.3:o:linux:linux_kernel:5.16:rc3:*:*:*:*:*:*"},{"vendor_slug":"linux","vendor_name":"linux","product_slug":"linux-kernel","product_name":"linux_kernel","version_start":"5.16","version_start_inclusive":true,"version_end":"5.16","version_end_inclusive":true,"cpe23_uri":"cpe:2.3:o:linux:linux_kernel:5.16:rc4:*:*:*:*:*:*"},{"vendor_slug":"linux","vendor_name":"linux","product_slug":"linux-kernel","product_name":"linux_kernel","version_start":"5.16","version_start_inclusive":true,"version_end":"5.16","version_end_inclusive":true,"cpe23_uri":"cpe:2.3:o:linux:linux_kernel:5.16:rc5:*:*:*:*:*:*"},{"vendor_slug":"linux","vendor_name":"linux","product_slug":"linux-kernel","product_name":"linux_kernel","version_start":"5.16","version_start_inclusive":true,"version_end":"5.16","version_end_inclusive":true,"cpe23_uri":"cpe:2.3:o:linux:linux_kernel:5.16:rc6:*:*:*:*:*:*"}],"exploit_refs":[],"news":[],"references":[{"url":"https://git.kernel.org/stable/c/9e291a6a28d32545ed2fd959a8165144d1724df1","source_type":"MISC","tags":[]},{"url":"https://git.kernel.org/stable/c/eabc0aab98e5218ceecd82069b0d6fdfff5ee885","source_type":"MISC","tags":[]},{"url":"https://git.kernel.org/stable/c/53b1119a6e5028b125f431a0116ba73510d82a72","source_type":"MISC","tags":[]}],"timeline":[{"type":"published","at":"2024-03-04T18:15:38.706000Z","label":"CVE published","source":null},{"type":"ssvc_changed","at":"2026-06-24T00:31:49.653458Z","label":"SSVC decision revised","source":"vulnrichment"},{"type":"ssvc_changed","at":"2026-06-24T00:31:49.653458Z","label":"SSVC decision revised","source":"vulnrichment"},{"type":"ssvc_changed","at":"2026-06-24T00:31:49.653458Z","label":"SSVC decision revised","source":"vulnrichment"},{"type":"cvss_changed","at":"2026-08-04T10:18:26.048314Z","label":"CVSS score revised","source":"vulnrichment"},{"type":"cvss_changed","at":"2026-08-04T10:18:26.048314Z","label":"CVSS score revised","source":"vulnrichment"},{"type":"cvss_changed","at":"2026-08-04T10:18:26.048314Z","label":"CVSS score revised","source":"vulnrichment"}]}