{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-98241","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-09-25T10:25:14.329Z","datePublished":"2026-10-06T08:45:11.954Z","dateUpdated":"2026-10-07T06:49:36.382Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-10-07T06:49:36.382Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: xfrm: use full sockets in local error paths\n\nxfrm6_local_rxpmtu() and xfrm6_local_error() dereference skb->sk as if it\nalways pointed at a full IPv6 socket.\n\nThat is not guaranteed. TCP SYN-ACK skbs can be owned by a\nTCP_NEW_SYN_RECV request_sock while the output path itself is driven by the\nfull listener. If rerouting selects an IPv6 XFRM tunnel route with a lower\nMTU, the local PMTU/error handling path can reach these callbacks with that\nmini-socket still attached to the skb.\n\nThe callbacks then miscast the request socket as a full inet/IPv6 socket and\ncan read beyond the request_sock allocation when they access inet_sock or\nipv6_pinfo state.\n\nResolve the owner with skb_to_full_sk() in both callbacks and bail out when\nno full socket is attached. This matches the surrounding XFRM IPv6 PMTU/error\nlogic, which already reasons about full sockets with skb_to_full_sk()."}],"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 fixed xfrm6_local_error() is reached via __xfrm6_output() -> xfrm_local_error() only if a rerouted SYN-ACK exceeds an xfrm tunnel MTU below ~100 bytes; that needs local xfrm/route/netfilter setup. A remote SYN carries no malformed data and can't create this state (IPv4 PMTU floor is 552, xfrm6_tunnel_check_size clamps to 1280).\nAC:L - The attacker builds every precondition: an IPv6-in-IPv4 tunnel-mode xfrm SA/policy, a tiny outer MTU, a LOCAL_OUT reroute, and a TCP listener they connect to. Each SYN deterministically sends a SYN-ACK owned by a TCP_NEW_SYN_RECV request_sock down the !ignore_df && toobig branch.\nPR:L - The needed XFRM_MSG_NEWSA/NEWPOLICY, nftables rules and link MTU changes only need CAP_NET_ADMIN in the netns, which an unprivileged user gets via unshare -Urn; the listener and connect() are ordinary syscalls.\nUI:N - The attacker sets up the namespace and drives the handshake that emits the SYN-ACK themselves; no other user has to do anything.\nS:U - The out-of-bounds access corrupts kernel heap memory in the same kernel that enforces the attacker's namespace; no hypervisor or IOMMU boundary is crossed.\nC:H - xfrm6_local_error() passes the request_sock to ipv6_local_error() as a full IPv6 socket; inet6_test_bit(RECVERR6) reads inet_flags past the end of the tcp6_request_sock allocation, into the next slab object, and the rest of the path keeps reading socket fields out of bounds.\nI:H - If the out-of-bounds RECVERR6 bit is set, sock_queue_err_skb() does atomic_add on an OOB sk_rmem_alloc, links an skb into an OOB sk_error_queue list and calls the OOB sk_error_report pointer: heap writes plus control-flow hijack if the attacker grooms the adjacent object.\nA:H - Treating neighbouring slab memory as sk_error_queue and sk_error_report gives list corruption or a wild indirect call, crashing the kernel; the attacker can repeat it with each SYN."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv6/xfrm6_output.c"],"versions":[{"version":"dd767856a36e00b631d65ebc4bb81b19915532d6","lessThan":"b1a88633c36d2cbc3831382f3846754d344276fd","status":"affected","versionType":"git"},{"version":"dd767856a36e00b631d65ebc4bb81b19915532d6","lessThan":"904a0e827d0d7189271a3a2eb648293809f25efc","status":"affected","versionType":"git"},{"version":"dd767856a36e00b631d65ebc4bb81b19915532d6","lessThan":"675919e08ce266b8cac11fd9af29170e762a480f","status":"affected","versionType":"git"},{"version":"dd767856a36e00b631d65ebc4bb81b19915532d6","lessThan":"60459c670329d586a58db5d8f811fa5accfe4862","status":"affected","versionType":"git"},{"version":"dd767856a36e00b631d65ebc4bb81b19915532d6","lessThan":"ca3d68c3213475b53db6647e159dc73bd1af5ab1","status":"affected","versionType":"git"},{"version":"dd767856a36e00b631d65ebc4bb81b19915532d6","lessThan":"4c030a0400ebfd2318361c923a88103b2c67c49f","status":"affected","versionType":"git"},{"version":"dd767856a36e00b631d65ebc4bb81b19915532d6","lessThan":"c21f3f7fbfeda7c5794f606cb0ffcc2d9001eef8","status":"affected","versionType":"git"},{"version":"dd767856a36e00b631d65ebc4bb81b19915532d6","lessThan":"6973a21ee73c5567f883813c8ef414774b45892f","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/xfrm6_output.c"],"versions":[{"version":"3.2","status":"affected"},{"version":"0","lessThan":"3.2","status":"unaffected","versionType":"semver"},{"version":"5.10.271","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.222","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.189","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.158","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.112","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.54","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.8","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3-rc4","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":"3.2","versionEndExcluding":"5.10.271"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.2","versionEndExcluding":"5.15.222"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.2","versionEndExcluding":"6.1.189"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.2","versionEndExcluding":"6.6.158"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.2","versionEndExcluding":"6.12.112"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.2","versionEndExcluding":"6.18.54"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.2","versionEndExcluding":"7.2.8"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.2","versionEndExcluding":"7.3-rc4"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/b1a88633c36d2cbc3831382f3846754d344276fd"},{"url":"https://git.kernel.org/stable/c/904a0e827d0d7189271a3a2eb648293809f25efc"},{"url":"https://git.kernel.org/stable/c/675919e08ce266b8cac11fd9af29170e762a480f"},{"url":"https://git.kernel.org/stable/c/60459c670329d586a58db5d8f811fa5accfe4862"},{"url":"https://git.kernel.org/stable/c/ca3d68c3213475b53db6647e159dc73bd1af5ab1"},{"url":"https://git.kernel.org/stable/c/4c030a0400ebfd2318361c923a88103b2c67c49f"},{"url":"https://git.kernel.org/stable/c/c21f3f7fbfeda7c5794f606cb0ffcc2d9001eef8"},{"url":"https://git.kernel.org/stable/c/6973a21ee73c5567f883813c8ef414774b45892f"}],"title":"ipv6: xfrm: use full sockets in local error paths","x_generator":{"engine":"bippy-1.2.0"}}}}