{"id":"CVE-2026-72253","state":"PUBLISHED","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.","publishedAt":"2026-08-15T05:54:41.490Z","updatedAt":"2026-10-16T18:55:13.536Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"cae3a2627520c3795b54533c5328b77af3405dbe","status":"affected","lessThan":"7866116a040b3a23fb094e7d8f7ea3d61b3ac70b","versionType":"git"},{"version":"cae3a2627520c3795b54533c5328b77af3405dbe","status":"affected","lessThan":"c5ef7228be04518d95591fc5369a9c554b19756d","versionType":"git"},{"version":"cae3a2627520c3795b54533c5328b77af3405dbe","status":"affected","lessThan":"0aec339694a56e263d4b22475ff7211d40900830","versionType":"git"},{"version":"cae3a2627520c3795b54533c5328b77af3405dbe","status":"affected","lessThan":"e64a48c50a1ff565a98c6a98d82b5b942868e76e","versionType":"git"},{"version":"cae3a2627520c3795b54533c5328b77af3405dbe","status":"affected","lessThan":"c199ed687c00841daf60e9d131976958583a8c09","versionType":"git"},{"version":"cae3a2627520c3795b54533c5328b77af3405dbe","status":"affected","lessThan":"09755dc62b026076b1d47f83489eb0547c8135e0","versionType":"git"},{"version":"cae3a2627520c3795b54533c5328b77af3405dbe","status":"affected","lessThan":"b843a96252f672332837ea2ecb7c8db0acf68e20","versionType":"git"},{"version":"cae3a2627520c3795b54533c5328b77af3405dbe","status":"affected","lessThan":"e5e24a365a5e024efef63cc49abb345fbd4852c5","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/netfilter/nf_conntrack_sip.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.3","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.3","versionType":"semver"},{"version":"5.10.266","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.217","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.184","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.148","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.101","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.42","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.5","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/netfilter/nf_conntrack_sip.c"]}],"references":["https://git.kernel.org/stable/c/7866116a040b3a23fb094e7d8f7ea3d61b3ac70b","https://git.kernel.org/stable/c/c5ef7228be04518d95591fc5369a9c554b19756d","https://git.kernel.org/stable/c/0aec339694a56e263d4b22475ff7211d40900830","https://git.kernel.org/stable/c/e64a48c50a1ff565a98c6a98d82b5b942868e76e","https://git.kernel.org/stable/c/c199ed687c00841daf60e9d131976958583a8c09","https://git.kernel.org/stable/c/09755dc62b026076b1d47f83489eb0547c8135e0","https://git.kernel.org/stable/c/b843a96252f672332837ea2ecb7c8db0acf68e20","https://git.kernel.org/stable/c/e5e24a365a5e024efef63cc49abb345fbd4852c5"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:58.252Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/72xxx/CVE-2026-72253.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-72253","state":"PUBLISHED","datePublished":"2026-08-15T05:54:41.490Z","dateUpdated":"2026-10-16T18:55:13.536Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-08-09T03:40:39.915Z"},"containers":{"cna":{"title":"netfilter: nf_conntrack_sip: validate skb_dst() before accessing it","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"cae3a2627520c3795b54533c5328b77af3405dbe","status":"affected","lessThan":"7866116a040b3a23fb094e7d8f7ea3d61b3ac70b","versionType":"git"},{"version":"cae3a2627520c3795b54533c5328b77af3405dbe","status":"affected","lessThan":"c5ef7228be04518d95591fc5369a9c554b19756d","versionType":"git"},{"version":"cae3a2627520c3795b54533c5328b77af3405dbe","status":"affected","lessThan":"0aec339694a56e263d4b22475ff7211d40900830","versionType":"git"},{"version":"cae3a2627520c3795b54533c5328b77af3405dbe","status":"affected","lessThan":"e64a48c50a1ff565a98c6a98d82b5b942868e76e","versionType":"git"},{"version":"cae3a2627520c3795b54533c5328b77af3405dbe","status":"affected","lessThan":"c199ed687c00841daf60e9d131976958583a8c09","versionType":"git"},{"version":"cae3a2627520c3795b54533c5328b77af3405dbe","status":"affected","lessThan":"09755dc62b026076b1d47f83489eb0547c8135e0","versionType":"git"},{"version":"cae3a2627520c3795b54533c5328b77af3405dbe","status":"affected","lessThan":"b843a96252f672332837ea2ecb7c8db0acf68e20","versionType":"git"},{"version":"cae3a2627520c3795b54533c5328b77af3405dbe","status":"affected","lessThan":"e5e24a365a5e024efef63cc49abb345fbd4852c5","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/netfilter/nf_conntrack_sip.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.3","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.3","versionType":"semver"},{"version":"5.10.266","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.217","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.184","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.148","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.101","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.42","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.5","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/netfilter/nf_conntrack_sip.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/7866116a040b3a23fb094e7d8f7ea3d61b3ac70b"},{"url":"https://git.kernel.org/stable/c/c5ef7228be04518d95591fc5369a9c554b19756d"},{"url":"https://git.kernel.org/stable/c/0aec339694a56e263d4b22475ff7211d40900830"},{"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"}],"metrics":[{"cvssV3_1":{"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"},"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":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-23T12:47:08.038Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.3","versionEndExcluding":"5.10.266"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.3","versionEndExcluding":"5.15.217"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.3","versionEndExcluding":"6.1.184"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.3","versionEndExcluding":"6.6.148"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.3","versionEndExcluding":"6.12.101"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.3","versionEndExcluding":"6.18.42"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.3","versionEndExcluding":"7.1.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.3","versionEndExcluding":"7.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-72253","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2026-10-16T18:45:17.838636Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-16T18:55:13.536Z"}}]}}}