{"cve":{"cve_id":"CVE-2026-62381","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":0.00076,"epss_percentile":0.00103,"epss_as_of":"2026-08-26","description":"luci-lib-px5g (LuCI) contains a heap-based buffer overflow in the native ASN.1 encoding routine asn1_add_obj (x509write.c) when signing a certificate with a 2040-bit RSA key. For a 255-byte signature, the BIT STRING allocation is computed from the DER length encoding of 255 bytes, but the payload written after prepending the unused-bits byte is 256 bytes, requiring one additional DER length octet. As a result the allocation is 259 bytes while the tag, length, unused-bits byte, and signature require 260 bytes, and the final memcpy writes one byte beyond the heap buffer. The overflow is reachable through the exported Lua interface via create_selfsigned(); whether it is remotely exploitable depends on the embedding application. The vulnerable code is present on the openwrt-18.06 through openwrt-25.12 release branches and is absent from master, where the luci-lib-px5g package has been removed rather than patched.","published_at":"2026-08-22T12:26:44.558000Z","last_modified_at":"2026-08-24T20:16:53.430000Z","cvss_v3_score":6.6,"cvss_v3_vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H","cvss_v3_severity":"MEDIUM","cvss_v4_score":6.9,"cvss_v4_vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N","cvss_v4_severity":"MEDIUM","ssvc_decision":null,"ssvc_exploitation":"poc","ssvc_automatable":false,"ssvc_technical_impact":"partial","cwes":["CWE-122"],"nvd_references":["https://github.com/openwrt/luci/security/advisories/GHSA-jgc3-4q3p-g6xh","https://www.vulncheck.com/advisories/luci-lib-px5g-2040-bit-certificate-signing-heap-buffer-overflow"],"vuln_status":"Received","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":"2026-08-22T12:42:27.513788Z","updated_at":"2026-08-26T17:38:41.391176Z"},"effective_severity":"MEDIUM","badges":[],"impact_analysis":[],"cvss_v3_decoded":{"version":"3.1","metrics":[{"metric":"AV","name":"Attack Vector","value":"L","value_label":"Local"},{"metric":"AC","name":"Attack Complexity","value":"L","value_label":"Low"},{"metric":"PR","name":"Privileges Required","value":"L","value_label":"Low"},{"metric":"UI","name":"User Interaction","value":"N","value_label":"None"},{"metric":"S","name":"Scope","value":"U","value_label":"Unchanged"},{"metric":"C","name":"Confidentiality","value":"L","value_label":"Low"},{"metric":"I","name":"Integrity","value":"L","value_label":"Low"},{"metric":"A","name":"Availability","value":"H","value_label":"High"}]},"cvss_v4_decoded":{"version":"4.0","metrics":[{"metric":"AV","name":"Attack Vector","value":"L","value_label":"Local"},{"metric":"AC","name":"Attack Complexity","value":"L","value_label":"Low"},{"metric":"AT","name":"Attack Requirements","value":"N","value_label":"None"},{"metric":"PR","name":"Privileges Required","value":"L","value_label":"Low"},{"metric":"UI","name":"User Interaction","value":"N","value_label":"None"},{"metric":"VC","name":"Confidentiality (Vulnerable System)","value":"L","value_label":"Low"},{"metric":"VI","name":"Integrity (Vulnerable System)","value":"L","value_label":"Low"},{"metric":"VA","name":"Availability (Vulnerable System)","value":"H","value_label":"High"},{"metric":"SC","name":"Confidentiality (Subsequent System)","value":"N","value_label":"None"},{"metric":"SI","name":"Integrity (Subsequent System)","value":"N","value_label":"None"},{"metric":"SA","name":"Availability (Subsequent System)","value":"N","value_label":"None"}]},"affected":[{"vendor_slug":"openwrt","vendor_name":"openwrt","product_slug":"luci","product_name":"luci","version_start":"0","version_start_inclusive":true,"version_end":"42d72f79cd8f057f241595abc761b39dab2d9f07","version_end_inclusive":true,"cpe23_uri":"cve5:openwrt:luci:0:42d72f79cd8f057f241595abc761b39dab2d9f07"}],"exploit_refs":[],"news":[],"references":[{"url":"https://github.com/openwrt/luci/security/advisories/GHSA-jgc3-4q3p-g6xh","source_type":"VENDOR_ADVISORY","tags":["advisory"]},{"url":"https://www.vulncheck.com/advisories/luci-lib-px5g-2040-bit-certificate-signing-heap-buffer-overflow","source_type":"VENDOR_ADVISORY","tags":["advisory"]}],"timeline":[{"type":"published","at":"2026-08-22T12:26:44.558000Z","label":"CVE published","source":null},{"type":"ssvc_changed","at":"2026-08-24T20:37:20.278232Z","label":"SSVC decision revised","source":"vulnrichment"},{"type":"ssvc_changed","at":"2026-08-24T20:37:20.278232Z","label":"SSVC decision revised","source":"vulnrichment"},{"type":"ssvc_changed","at":"2026-08-24T20:37:20.278232Z","label":"SSVC decision revised","source":"vulnrichment"}]}