{"api_version":"1","generated_at":"2026-08-22T06:11:56+00:00","cve":"CVE-2026-72253","urls":{"html":"https://cve.report/CVE-2026-72253","api":"https://cve.report/api/cve/CVE-2026-72253.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-72253","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-72253"},"summary":{"title":"netfilter: nf_conntrack_sip: validate skb_dst() before accessing it","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_conntrack_sip: validate skb_dst() before accessing it\n\ntc ingress and openvswitch do not guarantee routing information to be\navailable. These subsystems use the conntrack helper infrastructure, and\nthe SIP helper relies on the skb_dst() to be present if\nsip_external_media is set to 1 (which is disabled by default as a module\nparameter).\n\nThis effectively disables the sip_external_media toggle for these\nsubsystems without resulting in a crash.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-15 06:21:52","updated_at":"2026-08-17 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Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-72253","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected cae3a2627520c3795b54533c5328b77af3405dbe e64a48c50a1ff565a98c6a98d82b5b942868e76e git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected cae3a2627520c3795b54533c5328b77af3405dbe c199ed687c00841daf60e9d131976958583a8c09 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected cae3a2627520c3795b54533c5328b77af3405dbe 09755dc62b026076b1d47f83489eb0547c8135e0 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected cae3a2627520c3795b54533c5328b77af3405dbe b843a96252f672332837ea2ecb7c8db0acf68e20 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 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the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_conntrack_sip: validate skb_dst() before accessing it\n\ntc ingress and openvswitch do not guarantee routing information to be\navailable. These subsystems use the conntrack helper infrastructure, and\nthe SIP helper relies on the skb_dst() to be present if\nsip_external_media is set to 1 (which is disabled by default as a module\nparameter).\n\nThis effectively disables the sip_external_media toggle for these\nsubsystems without resulting in a crash."}],"metrics":[{"cvssV3_1":{"baseScore":7.5,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"scenarios":[{"lang":"en","value":"AV:N - Remote attackers reach set_expected_rtp_rtcp() by sending crafted SIP/SDP (e.g., INVITE) through Open vSwitch or tc ingress ct(helper=sip) on internet-facing VoIP SBC/NFV gateways where packets are conntrack-processed before skb_dst routing metadata is attached.\nAC:L - Once sip_external_media=1, sip_direct_media=0, and the SIP helper are configured on OVS/tc ingress, the attacker fully controls SIP/SDP contents to reach the skb_dst(skb)->dev dereference without races or conditions outside their control.\nPR:N - Exploitation requires no privileges on the victim host; a remote SIP peer only needs to deliver malicious signaling to an already-configured OVS/tc SIP ALG with sip_external_media enabled, with no authentication or local access.\nUI:N - No victim user interaction is required; the kernel SIP helper parses attacker-supplied SIP/SDP during conntrack processing in softirq without any user action beyond normal automated packet handling.\nS:U - A NULL pointer dereference in nf_conntrack_sip causes a kernel oops/panic within the same kernel security domain on the gateway; it does not cross VM, IOMMU, or sandbox boundaries.\nC:N - The failure is a direct NULL pointer dereference from skb_dst(skb) being NULL on tc/OVS ingress paths; there is no use-after-free, out-of-bounds read, or other memory disclosure primitive.\nI:N - Accessing skb_dst(skb)->dev when skb_dst is NULL cannot modify memory or hijack control flow beyond the immediate fault; CVSS guidance assigns None for pure NULL-deref crashes without write capability.\nA:H - The invalid skb_dst dereference in set_expected_rtp_rtcp() during SIP SDP processing causes a kernel oops/panic-class fault, denying availability on the VoIP gateway until reboot; the crash is reliably reproducible with crafted SIP traffic."}]}],"providerMetadata":{"dateUpdated":"2026-08-17T05:42:06.320Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/e64a48c50a1ff565a98c6a98d82b5b942868e76e"},{"url":"https://git.kernel.org/stable/c/c199ed687c00841daf60e9d131976958583a8c09"},{"url":"https://git.kernel.org/stable/c/09755dc62b026076b1d47f83489eb0547c8135e0"},{"url":"https://git.kernel.org/stable/c/b843a96252f672332837ea2ecb7c8db0acf68e20"},{"url":"https://git.kernel.org/stable/c/e5e24a365a5e024efef63cc49abb345fbd4852c5"}],"title":"netfilter: nf_conntrack_sip: validate skb_dst() before accessing it","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-72253","datePublished":"2026-08-15T05:54:41.490Z","dateReserved":"2026-08-09T03:40:39.915Z","dateUpdated":"2026-08-17T05:42:06.320Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-15 06:21:52","lastModifiedDate":"2026-08-17 06:18:27","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"},"exploitabilityScore":3.9,"impactScore":3.6}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"72253","Ordinal":"1","Title":"netfilter: nf_conntrack_sip: validate skb_dst() before accessing","CVE":"CVE-2026-72253","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"72253","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_conntrack_sip: validate skb_dst() before accessing it\n\ntc ingress and openvswitch do not guarantee routing information to be\navailable. These subsystems use the conntrack helper infrastructure, and\nthe SIP helper relies on the skb_dst() to be present if\nsip_external_media is set to 1 (which is disabled by default as a module\nparameter).\n\nThis effectively disables the sip_external_media toggle for these\nsubsystems without resulting in a crash.","Type":"Description","Title":"netfilter: nf_conntrack_sip: validate skb_dst() before accessing"}]}}}