{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-40158","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2025-04-16T07:20:57.176Z","datePublished":"2025-11-12T10:23:29.516Z","dateUpdated":"2026-08-05T12:08:08.096Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T12:08:08.096Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: use RCU in ip6_output()\n\nUse RCU in ip6_output() in order to use dst_dev_rcu() to prevent\npossible UAF.\n\nWe can remove rcu_read_lock()/rcu_read_unlock() pairs\nfrom ip6_finish_output2()."}],"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_output()` is the IPv6 egress path for *forwarded* packets — `ip6_forward()` → `ip6_forward_finish()` → `dst_output()` → `ip6_output()` — so a remote, unauthenticated attacker's IPv6 traffic drives the vulnerable function on any Linux router, gateway, or container/cloud host, matching sibling CVE-2025-40168 in the same dst_dev_rcu series.\nAC:H - The remote attacker supplies the traffic side of the race freely, but the `dst_dev_put()` side (netdev unregister/link down, veth deletion, route-exception teardown) is an operational event they cannot influence from the network, and the freed `inet6_dev`/`net_device` must be reallocated with useful content to escalate beyond a crash.\nPR:N - Packets on the forwarding path reach `ip6_output()` with no credentials, no socket, and no local account on the target — the router transmits them automatically. (Even in the purely local framing the netns/CAP_NET_ADMIN half is obtainable via `unshare -Urn`, so no real privilege is required either way.)\nUI:N - Transmission and forwarding happen unconditionally in softirq/process context on packet arrival; no administrator or local user has to open, mount, or click anything.\nS:U - The freed `inet6_dev` and `net_device` are kernel objects and the corruption stays 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 `idev->cnf.disable_ipv6`, `idev->stats.ipv6`, `dev->hard_header_len`/`needed_headroom`, `dev->header_ops` and `dev->flags`; once the freed slab object is reallocated the attacker can steer header-expansion sizes and the egress device, yielding kernel memory disclosure and out-of-device packet leakage.\nI:H - `IP6_INC_STATS`/`IP6_UPD_PO_STATS` expand to `SNMP_INC_STATS64(idev->stats.ipv6, field)`, performing a 64-bit increment through a per-CPU pointer loaded from freed memory — an arbitrary-write primitive after reallocation — and `neigh_output()` → `dev_queue_xmit()` makes an indirect call through `dev->netdev_ops->ndo_start_xmit` read from the freed `net_device`, giving control-flow hijack.\nA:H - Dereferencing a freed `inet6_dev`/`net_device` on the packet transmit path reliably oopses or panics the kernel (KASAN slab-use-after-free), and the crash is in the core IPv6 output path so it takes down the whole forwarding 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":"0393f85c3241c19ba8550f04a812e7d19f6b3082","status":"affected","versionType":"git"},{"version":"4a6ce2b6f2ecabbddcfe47e7cf61dd0f00b10e36","lessThan":"11709573cc4e48dc34c80fc7ab9ce5b159e29695","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":"6.17.3","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":"6.17.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.13","versionEndExcluding":"6.18"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/0393f85c3241c19ba8550f04a812e7d19f6b3082"},{"url":"https://git.kernel.org/stable/c/11709573cc4e48dc34c80fc7ab9ce5b159e29695"}],"title":"ipv6: use RCU in ip6_output()","x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-06-16T20:00:29.008533Z","id":"CVE-2025-40158","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":"2026-06-16T20:00:37.150Z"}}]}}