{ "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-2023-53585", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2023-53585", "idYear": 2023, "status": "PUBLISHED", "publishedAt": "2025-10-04T15:44:01.022Z", "updatedAt": "2026-05-11T19:47:54.787Z", "importedAt": "2026-10-24T01:57:03.413Z", "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": "bpf: reject unhashed sockets in bpf_sk_assign", "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: reject unhashed sockets in bpf_sk_assign\n\nThe semantics for bpf_sk_assign are as follows:\n\n sk = some_lookup_func()\n bpf_sk_assign(skb, sk)\n bpf_sk_release(sk)\n\nThat is, the sk is not consumed by bpf_sk_assign. The function\ntherefore needs to make sure that sk lives long enough to be\nconsumed from __inet_lookup_skb. The path through the stack for a\nTCPv4 packet is roughly:\n\n netif_receive_skb_core: takes RCU read lock\n __netif_receive_skb_core:\n sch_handle_ingress:\n tcf_classify:\n bpf_sk_assign()\n deliver_ptype_list_skb:\n deliver_skb:\n ip_packet_type->func == ip_rcv:\n ip_rcv_core:\n ip_rcv_finish_core:\n dst_input:\n ip_local_deliver:\n ip_local_deliver_finish:\n ip_protocol_deliver_rcu:\n tcp_v4_rcv:\n __inet_lookup_skb:\n skb_steal_sock\n\nThe existing helper takes advantage of the fact that everything\nhappens in the same RCU critical section: for sockets with\nSOCK_RCU_FREE set bpf_sk_assign never takes a reference.\nskb_steal_sock then checks SOCK_RCU_FREE again and does sock_put\nif necessary.\n\nThis approach assumes that SOCK_RCU_FREE is never set on a sk\nbetween bpf_sk_assign and skb_steal_sock, but this invariant is\nviolated by unhashed UDP sockets. A new UDP socket is created\nin TCP_CLOSE state but without SOCK_RCU_FREE set. That flag is only\nadded in udp_lib_get_port() which happens when a socket is bound.\n\nWhen bpf_sk_assign was added it wasn't possible to access unhashed\nUDP sockets from BPF, so this wasn't a problem. This changed\nin commit 0c48eefae712 (\"sock_map: Lift socket state restriction\nfor datagram sockets\"), but the helper wasn't adjusted accordingly.\nThe following sequence of events will therefore lead to a refcount\nleak:\n\n1. Add socket(AF_INET, SOCK_DGRAM) to a sockmap.\n2. Pull socket out of sockmap and bpf_sk_assign it. Since\n SOCK_RCU_FREE is not set we increment the refcount.\n3. bind() or connect() the socket, setting SOCK_RCU_FREE.\n4. skb_steal_sock will now set refcounted = false due to\n SOCK_RCU_FREE.\n5. tcp_v4_rcv() skips sock_put().\n\nFix the problem by rejecting unhashed sockets in bpf_sk_assign().\nThis matches the behaviour of __inet_lookup_skb which is ultimately\nthe goal of bpf_sk_assign().", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "cf7fbe660f2dbd738ab58aea8e9b0ca6ad232449", "status": "affected", "versionType": "git", "lessThan": "791a12102e5191dcb6ce0b3a99d71b5a2802d12a" }, { "version": "cf7fbe660f2dbd738ab58aea8e9b0ca6ad232449", "status": "affected", "versionType": "git", "lessThan": "7dcbc0bb0e5cc1823923744befce59ac353135e6" }, { "version": "cf7fbe660f2dbd738ab58aea8e9b0ca6ad232449", "status": "affected", "versionType": "git", "lessThan": "c0ce0fb76610d5fad31f56f2ca8241a2a6717a1b" }, { "version": "cf7fbe660f2dbd738ab58aea8e9b0ca6ad232449", "status": "affected", "versionType": "git", "lessThan": "8aa43cfbb68b25119d2ced14ec717173e2901fa2" }, { "version": "cf7fbe660f2dbd738ab58aea8e9b0ca6ad232449", "status": "affected", "versionType": "git", "lessThan": "3d4522f59fb748a54446846522941a4f09da63e9" }, { "version": "cf7fbe660f2dbd738ab58aea8e9b0ca6ad232449", "status": "affected", "versionType": "git", "lessThan": "67312adc96b5a585970d03b62412847afe2c6b01" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "5.7", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "5.7" }, { "version": "5.10.195", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.10.*" }, { "version": "5.15.132", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.15.*" }, { "version": "6.1.53", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.1.*" }, { "version": "6.4.16", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.4.*" }, { "version": "6.5.3", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.5.*" }, { "version": "6.6", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }