{"cve":"CVE-2026-64403","nvd":{"published":"2026-07-25T10:17:23.850","modified":"2026-10-19T21:17:35.757","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: L2CAP: validate option length before reading conf opt value\n\nl2cap_get_conf_opt() derives the option length from the\nattacker-controlled opt->len field and immediately dereferences\nopt->val (as u8, get_unaligned_le16() or get_unaligned_le32(), or a\nraw pointer for the default case) before any caller has confirmed\nthat opt->len bytes are present in the buffer. The callers\n(l2cap_parse_conf_req(), l2cap_parse_conf_rsp() and\nl2cap_conf_rfc_get()) only detect a malformed option afterwards, once\nthe running length has gone negative, by which point the\nout-of-bounds read has already executed.\n\nAn existing post-hoc length check keeps the garbage value from being\nconsumed, so this is not a data leak in the current control flow. It\nis still a validate-after-use ordering bug: up to 4 bytes are read\npast the end of the buffer before it is known to contain them, and it\nis fragile to future changes in the callers.\n\nFix it at the source. Pass the end of the buffer into\nl2cap_get_conf_opt() and refuse to touch opt->val unless the full\noption (header + value) fits. Each caller computes an end pointer\nonce before the loop and checks the return value directly instead of\ninferring the error from a negative length.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H","score":7.1},"cwes":["CWE-476","CWE-125"],"references":["https://git.kernel.org/stable/c/687617555cedfb74c9e3cb85d759b908dcb17856","https://git.kernel.org/stable/c/6b47bdaacfd0045687880177e0987055d8f4765a","https://git.kernel.org/stable/c/73abbaf91aa33da87c008fb62c148ade561bb606","https://git.kernel.org/stable/c/7d871e969b941ce25653f7716203a0ea4d07ad4b","https://git.kernel.org/stable/c/98d93c226bdfaa79bbdd86981921d7f106374225"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-21T03:56:58.798400159+00:00"},"epss":{"cve":"CVE-2026-64403","score":0.00266,"percentile":0.18325,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}