{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-23095", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-01-13T15:37:45.963Z", "datePublished": "2026-02-04T16:08:17.990Z", "dateUpdated": "2026-08-05T12:20:14.188Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:20:14.188Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ngue: Fix skb memleak with inner IP protocol 0.\n\nsyzbot reported skb memleak below. [0]\n\nThe repro generated a GUE packet with its inner protocol 0.\n\ngue_udp_recv() returns -guehdr->proto_ctype for \"resubmit\"\nin ip_protocol_deliver_rcu(), but this only works with\nnon-zero protocol number.\n\nLet's drop such packets.\n\nNote that 0 is a valid number (IPv6 Hop-by-Hop Option).\n\nI think it is not practical to encap HOPOPT in GUE, so once\nsomeone starts to complain, we could pass down a resubmit\nflag pointer to distinguish two zeros from the upper layer:\n\n * no error\n * resubmit HOPOPT\n\n[0]\nBUG: memory leak\nunreferenced object 0xffff888109695a00 (size 240):\n comm \"syz.0.17\", pid 6088, jiffies 4294943096\n hex dump (first 32 bytes):\n 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................\n 00 40 c2 10 81 88 ff ff 00 00 00 00 00 00 00 00 .@..............\n backtrace (crc a84b336f):\n kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]\n slab_post_alloc_hook mm/slub.c:4958 [inline]\n slab_alloc_node mm/slub.c:5263 [inline]\n kmem_cache_alloc_noprof+0x3b4/0x590 mm/slub.c:5270\n __build_skb+0x23/0x60 net/core/skbuff.c:474\n build_skb+0x20/0x190 net/core/skbuff.c:490\n __tun_build_skb drivers/net/tun.c:1541 [inline]\n tun_build_skb+0x4a1/0xa40 drivers/net/tun.c:1636\n tun_get_user+0xc12/0x2030 drivers/net/tun.c:1770\n tun_chr_write_iter+0x71/0x120 drivers/net/tun.c:1999\n new_sync_write fs/read_write.c:593 [inline]\n vfs_write+0x45d/0x710 fs/read_write.c:686\n ksys_write+0xa7/0x170 fs/read_write.c:738\n do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n do_syscall_64+0xa4/0xf80 arch/x86/entry/syscall_64.c:94\n entry_SYSCALL_64_after_hwframe+0x77/0x7f" } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:N - GUE processes incoming UDP packets from the network. Once a GUE tunnel is configured (its intended purpose in datacenter/cloud deployments), any remote attacker can send crafted UDP packets to the GUE port to trigger the leak.\nAC:L - The attacker simply sends a UDP packet with a GUE header containing proto_ctype=0. No race conditions, no special timing, and no conditions beyond the attacker's control once the GUE tunnel endpoint exists.\nPR:N - No authentication or privileges are needed to send UDP packets to a GUE tunnel endpoint. The vulnerability is in the packet receive path which processes all incoming packets without any authentication gate.\nUI:N - No user interaction is required. The vulnerability is triggered purely by receiving a crafted network packet.\nS:U - The vulnerability affects kernel memory within the same security authority. No scope boundary (VM, sandbox, IOMMU) is crossed.\nC:N - This is a pure memory leak — the skb is not freed but no memory contents are disclosed to the attacker. There is no information disclosure path.\nI:N - This is a memory leak, not a memory corruption. No kernel data structures are modified or corrupted; the skb simply becomes unreachable and is never freed.\nA:H - The attacker can repeatedly send crafted GUE packets over the network at high rate, each leaking ~240 bytes of kernel memory. This amplifiable, remotely-triggered leak can exhaust kernel memory causing OOM conditions and system-wide denial of service." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/ipv4/fou_core.c" ], "versions": [ { "version": "37dd0247797b168ad1cc7f5dbec825a1ee66535b", "lessThan": "886f186328b718400dbf79e1bc8cbcbd710ab766", "status": "affected", "versionType": "git" }, { "version": "37dd0247797b168ad1cc7f5dbec825a1ee66535b", "lessThan": "380a82d36e37db49fd41ecc378c22fd29392e96a", "status": "affected", "versionType": "git" }, { "version": "37dd0247797b168ad1cc7f5dbec825a1ee66535b", "lessThan": "536f5bbc322eb1e175bdd1ced22b236a951c4d8f", "status": "affected", "versionType": "git" }, { "version": "37dd0247797b168ad1cc7f5dbec825a1ee66535b", "lessThan": "f87b9b7a618c82e7465e872eb10e14c803871892", "status": "affected", "versionType": "git" }, { "version": "37dd0247797b168ad1cc7f5dbec825a1ee66535b", "lessThan": "ce569b389a5c78d64788a5ea94560e17fa574b35", "status": "affected", "versionType": "git" }, { "version": "37dd0247797b168ad1cc7f5dbec825a1ee66535b", "lessThan": "5437a279804ced8088cabb945dba88a26d828f8c", "status": "affected", "versionType": "git" }, { "version": "37dd0247797b168ad1cc7f5dbec825a1ee66535b", "lessThan": "9a56796ad258786d3624eef5aefba394fc9bdded", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/ipv4/fou_core.c" ], "versions": [ { "version": "3.18", "status": "affected" }, { "version": "0", "lessThan": "3.18", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.249", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.199", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.162", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.122", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.68", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.8", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.19", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.18", "versionEndExcluding": "5.10.249" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.18", "versionEndExcluding": "5.15.199" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.18", "versionEndExcluding": "6.1.162" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.18", "versionEndExcluding": "6.6.122" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.18", "versionEndExcluding": "6.12.68" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.18", "versionEndExcluding": "6.18.8" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.18", "versionEndExcluding": "6.19" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/886f186328b718400dbf79e1bc8cbcbd710ab766" }, { "url": "https://git.kernel.org/stable/c/380a82d36e37db49fd41ecc378c22fd29392e96a" }, { "url": "https://git.kernel.org/stable/c/536f5bbc322eb1e175bdd1ced22b236a951c4d8f" }, { "url": "https://git.kernel.org/stable/c/f87b9b7a618c82e7465e872eb10e14c803871892" }, { "url": "https://git.kernel.org/stable/c/ce569b389a5c78d64788a5ea94560e17fa574b35" }, { "url": "https://git.kernel.org/stable/c/5437a279804ced8088cabb945dba88a26d828f8c" }, { "url": "https://git.kernel.org/stable/c/9a56796ad258786d3624eef5aefba394fc9bdded" } ], "title": "gue: Fix skb memleak with inner IP protocol 0.", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "timestamp": "2026-06-16T20:19:57.582925Z", "id": "CVE-2026-23095", "options": [ { "Exploitation": "none" }, { "Automatable": "yes" }, { "Technical Impact": "partial" } ], "role": "CISA Coordinator", "version": "2.0.3" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-06-16T20:20:08.686Z" } }, { "x_adpType": "supplier", "providerMetadata": { "orgId": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e", "shortName": "siemens-SADP", "dateUpdated": "2026-07-14T12:46:00.351Z" }, "affected": [ { "vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.6", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" }, { "vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.6", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" }, { "vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.6", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" }, { "vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.6", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" }, { "vendor": "Siemens", "product": "SIPLUS S7-1500 CPU 1518-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.6", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" } ], "references": [ { "url": "https://cert-portal.siemens.com/productcert/html/ssa-019113.html" } ] } ] } }