{"id":"CVE-2025-39965","state":"PUBLISHED","title":"xfrm: xfrm_alloc_spi shouldn't use 0 as SPI","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: xfrm_alloc_spi shouldn't use 0 as SPI\n\nx->id.spi == 0 means \"no SPI assigned\", but since commit\n94f39804d891 (\"xfrm: Duplicate SPI Handling\"), we now create states\nand add them to the byspi list with this value.\n\n__xfrm_state_delete doesn't remove those states from the byspi list,\nsince they shouldn't be there, and this shows up as a UAF the next\ntime we go through the byspi list.","publishedAt":"2025-10-13T13:48:31.033Z","updatedAt":"2026-10-30T12:22:40.645Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"3d8090bb53424432fa788fe9a49e8ceca74f0544","status":"affected","lessThan":"0baf92d0b1590b903c1f4ead75e61715e50e8146","versionType":"git"},{"version":"2fc5b54368a1bf1d2d74b4d3b8eea5309a653e38","status":"affected","lessThan":"9fcedabaae0096f712bbb4ccca6a8538af1cd1c8","versionType":"git"},{"version":"29e9158f91f99057dbd35db5e8674d93b38549fe","status":"affected","lessThan":"a78e55776522373c446f18d5002a8de4b09e6bf7","versionType":"git"},{"version":"94f39804d891cffe4ce17737d295f3b195bc7299","status":"affected","lessThan":"cd8ae32e4e4652db55bce6b9c79267d8946765a9","versionType":"git"},{"version":"fb58962aa3b9359988c7b5b15a971fd9ad5b0ecd","status":"affected","versionType":"git"},{"version":"c67d4e7a8f90fb6361ca89d4d5c9a28f4e935e47","status":"affected","versionType":"git"},{"version":"6.1.191","status":"affected","lessThan":"6.2","versionType":"semver"},{"version":"6.15.11","status":"affected","lessThan":"6.16","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/xfrm/xfrm_state.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"6.6.103","status":"affected","lessThan":"6.6.109","versionType":"semver"},{"version":"6.12.43","status":"affected","lessThan":"6.12.50","versionType":"semver"},{"version":"6.16.2","status":"affected","lessThan":"6.16.10","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/xfrm/xfrm_state.c"]}],"references":["https://git.kernel.org/stable/c/0baf92d0b1590b903c1f4ead75e61715e50e8146","https://git.kernel.org/stable/c/9fcedabaae0096f712bbb4ccca6a8538af1cd1c8","https://git.kernel.org/stable/c/a78e55776522373c446f18d5002a8de4b09e6bf7","https://git.kernel.org/stable/c/cd8ae32e4e4652db55bce6b9c79267d8946765a9"],"weaknesses":[],"ingestedAt":"2026-10-30T12:40:04.423Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2025/39xxx/CVE-2025-39965.json","commit":"db8103c5921aac81d5d90efcf3745980dafabf49","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-39965","state":"PUBLISHED","datePublished":"2025-10-13T13:48:31.033Z","dateUpdated":"2026-10-30T12:22:40.645Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2025-04-16T07:20:57.149Z"},"containers":{"cna":{"title":"xfrm: xfrm_alloc_spi shouldn't use 0 as SPI","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: xfrm_alloc_spi shouldn't use 0 as SPI\n\nx->id.spi == 0 means \"no SPI assigned\", but since commit\n94f39804d891 (\"xfrm: Duplicate SPI Handling\"), we now create states\nand add them to the byspi list with this value.\n\n__xfrm_state_delete doesn't remove those states from the byspi list,\nsince they shouldn't be there, and this shows up as a UAF the next\ntime we go through the byspi list."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"3d8090bb53424432fa788fe9a49e8ceca74f0544","status":"affected","lessThan":"0baf92d0b1590b903c1f4ead75e61715e50e8146","versionType":"git"},{"version":"2fc5b54368a1bf1d2d74b4d3b8eea5309a653e38","status":"affected","lessThan":"9fcedabaae0096f712bbb4ccca6a8538af1cd1c8","versionType":"git"},{"version":"29e9158f91f99057dbd35db5e8674d93b38549fe","status":"affected","lessThan":"a78e55776522373c446f18d5002a8de4b09e6bf7","versionType":"git"},{"version":"94f39804d891cffe4ce17737d295f3b195bc7299","status":"affected","lessThan":"cd8ae32e4e4652db55bce6b9c79267d8946765a9","versionType":"git"},{"version":"fb58962aa3b9359988c7b5b15a971fd9ad5b0ecd","status":"affected","versionType":"git"},{"version":"c67d4e7a8f90fb6361ca89d4d5c9a28f4e935e47","status":"affected","versionType":"git"},{"version":"6.1.191","status":"affected","lessThan":"6.2","versionType":"semver"},{"version":"6.15.11","status":"affected","lessThan":"6.16","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/xfrm/xfrm_state.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"6.6.103","status":"affected","lessThan":"6.6.109","versionType":"semver"},{"version":"6.12.43","status":"affected","lessThan":"6.12.50","versionType":"semver"},{"version":"6.16.2","status":"affected","lessThan":"6.16.10","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/xfrm/xfrm_state.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/0baf92d0b1590b903c1f4ead75e61715e50e8146"},{"url":"https://git.kernel.org/stable/c/9fcedabaae0096f712bbb4ccca6a8538af1cd1c8"},{"url":"https://git.kernel.org/stable/c/a78e55776522373c446f18d5002a8de4b09e6bf7"},{"url":"https://git.kernel.org/stable/c/cd8ae32e4e4652db55bce6b9c79267d8946765a9"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The vulnerability is reached through the XFRM_MSG_ALLOCSPI message on a NETLINK_XFRM socket, which requires local system access. Although the dangling byspi entry can subsequently be dereferenced by a received ESP/AH packet, creating the SPI-0 state requires the local netlink path.\nAC:L - The attacker deterministically triggers the bug by requesting min=max=0, which verify_spi_info() accepts, then deleting the state via DELSA/FLUSHSA; there is no race, no memory-layout dependency, and no non-default config beyond ubiquitous CONFIG_XFRM_USER.\nPR:L - xfrm_user_rcv_msg() gates on netlink_net_capable(skb, CAP_NET_ADMIN), which is evaluated against the net namespace's user_ns, so any unprivileged user obtains it via \"unshare -Urn\". This is Low, not High.\nUI:N - The full sequence — allocate SPI 0, delete the state, re-walk the byspi hash — is performed entirely by the attacker's own process with no victim action required.\nS:U - The freed xfrm_state and the corrupted hash list both live in the kernel's own security authority; this is standard kernel memory corruption with no VM, IOMMU, or hypervisor boundary crossed.\nC:H - The dangling xfrm_state remains in a global RCU hash and is read back and returned as a live SA, so a reclaimed object leaks adjacent heap contents and crypto/key state, and the UAF can be escalated into an arbitrary kernel read primitive.\nI:H - Walkers perform refcount_inc_not_zero on the freed object (a write to freed memory) and then use it as a live SA whose type/mode function-pointer fields the attacker can control by re-spraying the xfrm_state slab, yielding control-flow hijack and arbitrary write.\nA:H - Dereferencing the freed state during byspi traversal, hash resize, or netns teardown (WARN_ON(!hlist_empty())) reliably produces a KASAN-detected use-after-free, list corruption, and kernel panic."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:22:40.645Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6.103","versionEndExcluding":"6.6.109"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12.43","versionEndExcluding":"6.12.50"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.16.2","versionEndExcluding":"6.16.10"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.15.11"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2025-39965","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-15T21:55:18.566568Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-15T22:02:34.319Z"}}]}}}