{ "schemaVersion": 1, "attribution": [ { "source": "CISA Known Exploited Vulnerabilities", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog", "licence": "US government work" }, { "source": "GitHub Advisory Database", "url": "https://github.com/advisories", "licence": "CC BY 4.0" }, { "source": "Have I Been Pwned", "url": "https://haveibeenpwned.com/", "licence": "CC BY 4.0" }, { "source": "CVE Program (CVE records)", "url": "https://www.cve.org/Legal/TermsOfUse", "licence": "CVE Terms of Use", "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.", "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." }, { "source": "FIRST EPSS", "url": "https://www.first.org/epss/", "licence": "free to use; FIRST requests attribution" } ], "record": { "id": "CVE-2026-64177", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-64177", "idYear": 2026, "status": "PUBLISHED", "publishedAt": "2026-07-19T15:41:01.534Z", "updatedAt": "2026-07-19T15:41:01.534Z", "importedAt": "2026-10-24T01:58:25.636Z", "snapshot": { "id": "cve_2026-10-24_midnight_baseline", "at": "2026-10-24T00:00:00.000Z", "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z" }, "facts": { "title": "phonet/pep: disable BH around forwarded sk_receive_skb()", "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nphonet/pep: disable BH around forwarded sk_receive_skb()\n\nThe networking receive path is usually run from softirq context, but\nprotocols that take the socket lock may have packets stored in the\nbacklog and processed later from process context. In that case\nrelease_sock() -> __release_sock() drops the slock with spin_unlock_bh()\nand then calls sk->sk_backlog_rcv() with bottom halves enabled.\n\nTypical sk_backlog_rcv handlers process the socket whose backlog is\nbeing drained, so the BH state at entry is irrelevant for the slocks\nthey touch. pep_do_rcv() is different: when the inbound skb targets an\nexisting PEP pipe, it forwards the skb to a different *child* socket\nvia sk_receive_skb(). That helper takes the child slock with\nbh_lock_sock_nested(), which is just spin_lock_nested() and assumes BH\nis already off. The same child slock therefore ends up acquired with\nBH on (process path) and with BH off (softirq path):\n\n process context softirq context\n --------------- ---------------\n release_sock(listener) __netif_receive_skb()\n __release_sock() phonet_rcv()\n spin_unlock_bh() __sk_receive_skb(listener)\n [BH now ENABLED] [BH already disabled]\n sk_backlog_rcv: sk_backlog_rcv:\n pep_do_rcv() pep_do_rcv()\n sk_receive_skb(child) sk_receive_skb(child)\n bh_lock_sock_nested(child) bh_lock_sock_nested(child)\n => SOFTIRQ-ON-W => IN-SOFTIRQ-W\n\nLockdep flags this as inconsistent lock state, and it can become a real\nself-deadlock if a softirq on the same CPU tries to receive to the same\nchild socket while its slock is held in the BH-enabled path:\n\n WARNING: inconsistent lock state\n inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.\n (slock-AF_PHONET/1){+.?.}-{3:3}, at: __sk_receive_skb+0x1cf/0x900\n __sk_receive_skb net/core/sock.c:563\n sk_receive_skb include/net/sock.h:2022 [inline]\n pep_do_rcv net/phonet/pep.c:675\n sk_backlog_rcv include/net/sock.h:1190\n __release_sock net/core/sock.c:3216\n release_sock net/core/sock.c:3815\n pep_sock_accept net/phonet/pep.c:879\n\nWrap the forwarded sk_receive_skb() in local_bh_disable() /\nlocal_bh_enable() so the child slock is always acquired with BH off.\nlocal_bh_disable() nests safely on the softirq path.\n\nDiscovered via in-house syzkaller fuzzing; the same root cause also\non the linux-6.1.y syzbot dashboard as extid 44f0626dd6284f02663c.\nReproduced under KASAN + LOCKDEP + PROVE_LOCKING, reproducer:\nhttps://pastebin.com/A3t8xzCR", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "9641458d3ec42def729fde64669abf07f3220cd5", "status": "affected", "versionType": "git", "lessThan": "f08c45076e4fd8b0adbc5eb186d6e6a3e7350d7b" }, { "version": "9641458d3ec42def729fde64669abf07f3220cd5", "status": "affected", "versionType": "git", "lessThan": "b2606c302d7f2b4ee48da05e32ed60aed1b0cd53" }, { "version": "9641458d3ec42def729fde64669abf07f3220cd5", "status": "affected", "versionType": "git", "lessThan": "02c04df84de709060f63e1d52ec67488c4f6f212" }, { "version": "9641458d3ec42def729fde64669abf07f3220cd5", "status": "affected", "versionType": "git", "lessThan": "8420aa4900417797323dd567ba9d1512280c2dc3" }, { "version": "9641458d3ec42def729fde64669abf07f3220cd5", "status": "affected", "versionType": "git", "lessThan": "bd795f106b3889fb0706c6e4831c4b27e2b5666b" }, { "version": "9641458d3ec42def729fde64669abf07f3220cd5", "status": "affected", "versionType": "git", "lessThan": "84bc87beb4cd77670939b446326788e4c9b3db37" }, { "version": "9641458d3ec42def729fde64669abf07f3220cd5", "status": "affected", "versionType": "git", "lessThan": "a3fc8f2dacd1c37325977fc1fbbf3d52141df99e" }, { "version": "9641458d3ec42def729fde64669abf07f3220cd5", "status": "affected", "versionType": "git", "lessThan": "dbc81608e3a653dea6cf403f20cae35468b8ab9c" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "2.6.28", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "2.6.28" }, { "version": "5.10.258", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.10.*" }, { "version": "5.15.209", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.15.*" }, { "version": "6.1.175", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.1.*" }, { "version": "6.6.142", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.6.*" }, { "version": "6.12.92", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.12.*" }, { "version": "6.18.34", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.18.*" }, { "version": "7.0.11", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "7.0.*" }, { "version": "7.1", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }