{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-21765", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-12-29T08:45:45.761Z", "datePublished": "2025-02-27T02:18:16.078Z", "dateUpdated": "2026-08-05T11:54:18.497Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:54:18.497Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: use RCU protection in ip6_default_advmss()\n\nip6_default_advmss() needs rcu protection to make\nsure the net structure it reads does not disappear." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 8.1, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:N - `ip6_default_advmss()` is reached from the inbound IPv6 TCP handshake — `tcp_v6_rcv()` → `tcp_conn_request()` → `tcp_openreq_init_rwin()` and `tcp_v6_send_synack()` → `tcp_make_synack()` — so an unauthenticated remote peer sending a TCP SYN to any listening IPv6 socket executes the vulnerable read. No local access is needed.\nAC:H - The use-after-free only materialises if the `struct net` obtained from `dev_net(dst->dev)` is concurrently torn down (netns dismantle or `dev_change_net_namespace()`), a condition a remote attacker cannot influence, and the unprotected window between the pointer load and the `ip6_rt_min_advmss` dereference is narrow.\nPR:N - There is no privilege, capability or authentication check anywhere on the path; the code runs in softirq during SYN processing before any connection is established or credentials exchanged.\nUI:N - The attacker triggers the path entirely by transmitting packets to a listening IPv6 port; no action by a local user or victim process is required.\nS:U - The stale `struct net` dereference is confined to the kernel's own networking stack on the same host, crossing no virtualization, IOMMU or other security-authority boundary.\nC:H - This is a use-after-free read of a freed `net_cachep` slab object, and the recovered value directly influences the MSS advertised in the SYN-ACK, exposing reallocated kernel heap contents to the remote peer as an oracle.\nI:H - Reuse of a freed `struct net` means kernel state is derived from attacker-groomable reallocated slab memory; per UAF scoring guidance such object reuse is treated as corruption exploitable for further modification of kernel state.\nA:H - Dereferencing a `struct net` that has already been returned to the slab allocator can fault or read garbage, producing a KASAN splat, oops or panic in the TCP receive softirq path, and the trigger is repeatable with ordinary inbound connections." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/ipv6/route.c" ], "versions": [ { "version": "5578689a4e3c04f2d43ea39736fd3fa396d80c6e", "lessThan": "78ad057472d8c76e0602402269222f9f9c698790", "status": "affected", "versionType": "git" }, { "version": "5578689a4e3c04f2d43ea39736fd3fa396d80c6e", "lessThan": "d02f30d220ef9511568a48dba8a9004c65f8d904", "status": "affected", "versionType": "git" }, { "version": "5578689a4e3c04f2d43ea39736fd3fa396d80c6e", "lessThan": "28de355b63ad42309ed5a03ee7c436c90512265b", "status": "affected", "versionType": "git" }, { "version": "5578689a4e3c04f2d43ea39736fd3fa396d80c6e", "lessThan": "84212387caadb211cd9dadd6fd5563bd37dc1f5e", "status": "affected", "versionType": "git" }, { "version": "5578689a4e3c04f2d43ea39736fd3fa396d80c6e", "lessThan": "4176a68b0db8fc74ac14fcd00ba8231371051dc2", "status": "affected", "versionType": "git" }, { "version": "5578689a4e3c04f2d43ea39736fd3fa396d80c6e", "lessThan": "713a40c892f40300d63691d9f85b2a23b48fe1e8", "status": "affected", "versionType": "git" }, { "version": "5578689a4e3c04f2d43ea39736fd3fa396d80c6e", "lessThan": "550ed693f47370502a71b85382e7f9e6417300b8", "status": "affected", "versionType": "git" }, { "version": "5578689a4e3c04f2d43ea39736fd3fa396d80c6e", "lessThan": "3c8ffcd248da34fc41e52a46e51505900115fc2a", "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/ipv6/route.c" ], "versions": [ { "version": "2.6.26", "status": "affected" }, { "version": "0", "lessThan": "2.6.26", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.291", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.235", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.179", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.129", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.79", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.16", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.13.4", "lessThanOrEqual": "6.13.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.14", "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": "2.6.26", "versionEndExcluding": "5.4.291" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.26", "versionEndExcluding": "5.10.235" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.26", "versionEndExcluding": "5.15.179" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.26", "versionEndExcluding": "6.1.129" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.26", "versionEndExcluding": "6.6.79" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.26", "versionEndExcluding": "6.12.16" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.26", "versionEndExcluding": "6.13.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.26", "versionEndExcluding": "6.14" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/78ad057472d8c76e0602402269222f9f9c698790" }, { "url": "https://git.kernel.org/stable/c/d02f30d220ef9511568a48dba8a9004c65f8d904" }, { "url": "https://git.kernel.org/stable/c/28de355b63ad42309ed5a03ee7c436c90512265b" }, { "url": "https://git.kernel.org/stable/c/84212387caadb211cd9dadd6fd5563bd37dc1f5e" }, { "url": "https://git.kernel.org/stable/c/4176a68b0db8fc74ac14fcd00ba8231371051dc2" }, { "url": "https://git.kernel.org/stable/c/713a40c892f40300d63691d9f85b2a23b48fe1e8" }, { "url": "https://git.kernel.org/stable/c/550ed693f47370502a71b85382e7f9e6417300b8" }, { "url": "https://git.kernel.org/stable/c/3c8ffcd248da34fc41e52a46e51505900115fc2a" } ], "title": "ipv6: use RCU protection in ip6_default_advmss()", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "title": "CVE Program Container", "references": [ { "url": "https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html" }, { "url": "https://lists.debian.org/debian-lts-announce/2025/03/msg00028.html" } ], "providerMetadata": { "orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2025-11-03T19:37:20.115Z" } }, { "x_adpType": "supplier", "providerMetadata": { "orgId": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e", "shortName": "siemens-SADP", "dateUpdated": "2026-07-14T12:40:03.462Z" }, "affected": [ { "vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.5", "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 1518-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.5", "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": "V3.1.5", "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": "V3.1.5", "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 TM MFP - GNU/Linux subsystem", "versions": [ { "status": "affected", "version": "0", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" }, { "vendor": "Siemens", "product": "SIPLUS S7-1500 CPU 1518-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.5", "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-265688.html" }, { "url": "https://cert-portal.siemens.com/productcert/html/ssa-082556.html" }, { "url": "https://cert-portal.siemens.com/productcert/html/ssa-019113.html" } ] } ] } }