{"schemaVersion":3,"id":"CVE-2026-62381","aliases":[],"status":"published","duplicateOf":null,"title":null,"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.","dates":{"published":"2026-08-22T12:26:44.558Z","modified":"2026-08-24T19:50:50.874Z","reserved":null,"kevAdded":[],"kevDue":[]},"cvss":{"headline":{"score":6.9,"severity":"medium","version":"4.0","versionLabel":"v4.0","source":"CVE.org","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","computed":false,"selection":"backend-summary"},"metrics":[{"version":"4.0","versionLabel":"v4.0","source":"CVE.org","score":6.9,"severity":"medium","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","exploitability":null,"impact":null,"computed":false},{"version":"3.1","versionLabel":"v3.1","source":"CVE.org","score":6.6,"severity":"medium","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H","exploitability":null,"impact":null,"computed":false},{"version":"4.0","versionLabel":"v4.0","source":"NVD","score":6.9,"severity":"medium","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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","exploitability":null,"impact":null,"computed":false},{"version":"3.1","versionLabel":"v3.1","source":"NVD","score":6.6,"severity":"medium","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H","exploitability":null,"impact":null,"computed":false}]},"epss":{"probability":0.00108,"percentile":0.01124,"severity":"low","asOf":"2026-10-20T00:00:00.000Z","change":{"pp":0.032,"baselineDate":"2026-09-20T00:00:00.000Z","baselineScore":0.00076},"history":[{"date":"2026-09-14T00:00:00.000Z","score":0.00076,"percentile":null},{"date":"2026-09-15T00:00:00.000Z","score":0.00076,"percentile":null},{"date":"2026-09-16T00:00:00.000Z","score":0.00076,"percentile":null},{"date":"2026-09-17T00:00:00.000Z","score":0.00076,"percentile":null},{"date":"2026-09-18T00:00:00.000Z","score":0.00076,"percentile":null},{"date":"2026-09-19T00:00:00.000Z","score":0.00076,"percentile":null},{"date":"2026-09-20T00:00:00.000Z","score":0.00076,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.00076,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.00076,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.00076,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.00102,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.00108,"percentile":0.01124}],"last30":[{"date":"2026-09-20T00:00:00.000Z","score":0.00076,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.00076,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.00076,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.00076,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.00102,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.00108,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.00108,"percentile":0.01124}]},"kev":{"state":"not-listed","entries":[],"listedCount":0,"totalCatalogs":3,"catalogs":[{"source":"cisa","label":"CISA","listed":false,"entry":null},{"source":"enisa","label":"ENISA","listed":false,"entry":null},{"source":"circl","label":"CIRCL","listed":false,"entry":null}]},"ransomware":{"state":"none-recorded","sources":[]},"exploits":[],"exploitCount":0,"weaknesses":[{"id":"CWE-122","name":"Heap-based Buffer Overflow","description":"A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().","type":"weakness","status":"Draft","abstraction":"Variant","likelihoodOfExploit":"High","url":"https://cwe.mitre.org/data/definitions/122.html"}],"affected":[{"vendor":"openwrt","product":"luci","name":"luci","label":"luci","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"≤ 42d72f79cd8f057f241595abc761b39dab2d9f07","noFixRecorded":false,"fixedIn":null}],"versionsText":"≤ 42d72f79cd8f057f241595abc761b39dab2d9f07","eol":null,"hubHref":"/vendor/openwrt/luci"}],"affectedCount":1,"eol":{"hasEol":false,"count":0},"references":[{"url":"https://github.com/openwrt/luci/security/advisories/GHSA-jgc3-4q3p-g6xh","label":"github.com/openwrt/luci/security/advisories/GHSA-jgc3-4q3p-g6xh","hostname":"github.com","tags":["Vendor Advisory"]},{"url":"https://www.vulncheck.com/advisories/luci-lib-px5g-2040-bit-certificate-signing-heap-buffer-overflow","label":"www.vulncheck.com/advisories/luci-lib-px5g-2040-bit-certificate-signing-heap-buffer-overflow","hostname":"www.vulncheck.com","tags":["Third Party Advisory"]}],"lineage":{"upstream":[],"downstream":[],"duplicates":[],"related":[]},"timeline":[{"kind":"published","date":"2026-08-22T12:26:44.558Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"modified","date":"2026-08-24T19:50:50.874Z","label":"Last modified","detail":"Vulnerability information updated.","source":null}],"risk":{"score":28,"level":"medium","profile":"Default","thresholds":{"critical":75,"high":50,"medium":25,"low":10}},"meta":{"dataAsOf":"2026-10-21T11:33:33.791Z","stale":false,"partial":false}}