{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-40135", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T07:20:57.170Z", "datePublished": "2025-11-12T10:23:23.051Z", "dateUpdated": "2026-08-05T12:08:00.413Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:08:00.413Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: use RCU in ip6_xmit()\n\nUse RCU in ip6_xmit() in order to use dst_dev_rcu() to prevent\npossible UAF." } ], "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_xmit()` is the locally-originated IPv6 output path for TCP and SCTP, and is driven directly by remote packets — `tcp_v6_send_synack()` on an incoming SYN and `tcp_v6_send_response()` for RST/challenge-ACK both call it before any authentication. Any internet-facing host with an IPv6 TCP listener (or that merely replies with RST) exposes the vulnerable function to unauthenticated remote traffic.\nAC:H - The attacker freely supplies the transmit side of the race by sending TCP/SCTP traffic, but the `dst_dev_put()` side (netdev unregister/link-down, veth teardown, route-exception/pcpu-route destruction) is an operational event they cannot influence from the network, and escalating past a crash requires the freed `net_device`/`inet6_dev` slab object to be reallocated with attacker-useful content. This matches sibling CVE-2025-40158 and CVE-2025-40168 in the same dst_dev_rcu series.\nPR:N - SYNACK and RST generation happen with no credentials, no established session, and no local account on the target — the kernel transmits automatically on packet arrival. Even under a purely local framing, both halves of the race (IPv6 traffic plus veth create/delete and route flush) are available to any unprivileged user via `unshare -Urn`, so no real privilege is required either way.\nUI:N - Packet transmission occurs unconditionally in softirq or backlog-drain context when traffic arrives; no administrator or local user has to open, mount, configure, or click anything.\nS:U - The freed `net_device` and `inet6_dev` are kernel-internal objects and the resulting corruption stays entirely within the kernel's own security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - This is a use-after-free read of `dev->hard_header_len`/`needed_headroom` via `LL_RESERVED_SPACE()`, of `idev->stats.ipv6`, and of `out->name`/`out->ifindex` inside the `NF_HOOK(NF_INET_LOCAL_OUT)` traversal; once the freed slab object is reallocated the attacker can steer header-expansion sizing and the recorded egress device, yielding kernel memory disclosure and misdirected packet leakage.\nI:H - `IP6_INC_STATS(net, idev, ...)` expands to `SNMP_INC_STATS64(idev->stats.ipv6, field)`, performing a 64-bit increment through a per-CPU pointer loaded from freed memory — a write primitive after reallocation — and the stale `dev` propagates into `skb->dev` and the netfilter hook state, giving control over structures used for further dispatch.\nA:H - Dereferencing a freed `inet6_dev`/`net_device` on the IPv6 transmit path reliably produces a KASAN slab-use-after-free splat, oops, or panic, and because the fault is in the core TCP/SCTP egress path it takes down the entire host." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/ipv6/ip6_output.c" ], "versions": [ { "version": "4a6ce2b6f2ecabbddcfe47e7cf61dd0f00b10e36", "lessThan": "f0a54d00d2f36de40266f47c27989853e8588656", "status": "affected", "versionType": "git" }, { "version": "4a6ce2b6f2ecabbddcfe47e7cf61dd0f00b10e36", "lessThan": "f69fec6287565fdeb61f65e700a1184352306943", "status": "affected", "versionType": "git" }, { "version": "4a6ce2b6f2ecabbddcfe47e7cf61dd0f00b10e36", "lessThan": "bd0905e2122e3680968cd0741966983490bf2ed3", "status": "affected", "versionType": "git" }, { "version": "4a6ce2b6f2ecabbddcfe47e7cf61dd0f00b10e36", "lessThan": "f7f9e924f23684b4b23cd9f976cceab24a968e34", "status": "affected", "versionType": "git" }, { "version": "4a6ce2b6f2ecabbddcfe47e7cf61dd0f00b10e36", "lessThan": "9085e56501d93af9f2d7bd16f7fcfacdde47b99c", "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/ip6_output.c" ], "versions": [ { "version": "4.13", "status": "affected" }, { "version": "0", "lessThan": "4.13", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.167", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.130", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.78", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.17.3", "lessThanOrEqual": "6.17.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18", "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": "4.13", "versionEndExcluding": "6.1.167" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.13", "versionEndExcluding": "6.6.130" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.13", "versionEndExcluding": "6.12.78" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.13", "versionEndExcluding": "6.17.3" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.13", "versionEndExcluding": "6.18" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/f0a54d00d2f36de40266f47c27989853e8588656" }, { "url": "https://git.kernel.org/stable/c/f69fec6287565fdeb61f65e700a1184352306943" }, { "url": "https://git.kernel.org/stable/c/bd0905e2122e3680968cd0741966983490bf2ed3" }, { "url": "https://git.kernel.org/stable/c/f7f9e924f23684b4b23cd9f976cceab24a968e34" }, { "url": "https://git.kernel.org/stable/c/9085e56501d93af9f2d7bd16f7fcfacdde47b99c" } ], "title": "ipv6: use RCU in ip6_xmit()", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "timestamp": "2026-06-16T19:58:56.548938Z", "id": "CVE-2025-40135", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "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": "2026-06-16T19:59:06.997Z" } }, { "x_adpType": "supplier", "providerMetadata": { "orgId": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e", "shortName": "siemens-SADP", "dateUpdated": "2026-07-14T12:43:22.637Z" }, "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": "V3.1.5", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" }, { 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