CVE-2026-72253 (GCVE-0-2026-72253)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:54 – Updated: 2026-08-23 12:47
VLAI
Title
netfilter: nf_conntrack_sip: validate skb_dst() before accessing it
Summary
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack_sip: validate skb_dst() before accessing it tc ingress and openvswitch do not guarantee routing information to be available. These subsystems use the conntrack helper infrastructure, and the SIP helper relies on the skb_dst() to be present if sip_external_media is set to 1 (which is disabled by default as a module parameter). This effectively disables the sip_external_media toggle for these subsystems without resulting in a crash.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: cae3a2627520c3795b54533c5328b77af3405dbe , < 7866116a040b3a23fb094e7d8f7ea3d61b3ac70b (git)
Affected: cae3a2627520c3795b54533c5328b77af3405dbe , < c5ef7228be04518d95591fc5369a9c554b19756d (git)
Affected: cae3a2627520c3795b54533c5328b77af3405dbe , < 0aec339694a56e263d4b22475ff7211d40900830 (git)
Affected: cae3a2627520c3795b54533c5328b77af3405dbe , < e64a48c50a1ff565a98c6a98d82b5b942868e76e (git)
Affected: cae3a2627520c3795b54533c5328b77af3405dbe , < c199ed687c00841daf60e9d131976958583a8c09 (git)
Affected: cae3a2627520c3795b54533c5328b77af3405dbe , < 09755dc62b026076b1d47f83489eb0547c8135e0 (git)
Affected: cae3a2627520c3795b54533c5328b77af3405dbe , < b843a96252f672332837ea2ecb7c8db0acf68e20 (git)
Affected: cae3a2627520c3795b54533c5328b77af3405dbe , < e5e24a365a5e024efef63cc49abb345fbd4852c5 (git)
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Linux Linux Affected: 4.3
Unaffected: 0 , < 4.3 (semver)
Unaffected: 5.10.266 , ≤ 5.10.* (semver)
Unaffected: 5.15.217 , ≤ 5.15.* (semver)
Unaffected: 6.1.184 , ≤ 6.1.* (semver)
Unaffected: 6.6.148 , ≤ 6.6.* (semver)
Unaffected: 6.12.101 , ≤ 6.12.* (semver)
Unaffected: 6.18.42 , ≤ 6.18.* (semver)
Unaffected: 7.1.5 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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        {
          "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."
        }
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            "baseSeverity": "HIGH",
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              "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)-\u003edev 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)-\u003edev 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."
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        "shortName": "Linux"
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    "dateReserved": "2026-08-09T03:40:39.915Z",
    "dateUpdated": "2026-08-23T12:47:08.038Z",
    "state": "PUBLISHED"
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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\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"net/netfilter/nf_conntrack_sip.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"cae3a2627520c3795b54533c5328b77af3405dbe\",\"lessThan\":\"7866116a040b3a23fb094e7d8f7ea3d61b3ac70b\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"cae3a2627520c3795b54533c5328b77af3405dbe\",\"lessThan\":\"c5ef7228be04518d95591fc5369a9c554b19756d\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"cae3a2627520c3795b54533c5328b77af3405dbe\",\"lessThan\":\"0aec339694a56e263d4b22475ff7211d40900830\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"cae3a2627520c3795b54533c5328b77af3405dbe\",\"lessThan\":\"e64a48c50a1ff565a98c6a98d82b5b942868e76e\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"cae3a2627520c3795b54533c5328b77af3405dbe\",\"lessThan\":\"c199ed687c00841daf60e9d131976958583a8c09\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"cae3a2627520c3795b54533c5328b77af3405dbe\",\"lessThan\":\"09755dc62b026076b1d47f83489eb0547c8135e0\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"cae3a2627520c3795b54533c5328b77af3405dbe\",\"lessThan\":\"b843a96252f672332837ea2ecb7c8db0acf68e20\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"cae3a2627520c3795b54533c5328b77af3405dbe\",\"lessThan\":\"e5e24a365a5e024efef63cc49abb345fbd4852c5\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"net/netfilter/nf_conntrack_sip.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"4.3\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"4.3\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"5.10.266\",\"lessThanOrEqual\":\"5.10.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"5.15.217\",\"lessThanOrEqual\":\"5.15.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.1.184\",\"lessThanOrEqual\":\"6.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.6.148\",\"lessThanOrEqual\":\"6.6.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.101\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.42\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.5\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"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}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/09755dc62b026076b1d47f83489eb0547c8135e0\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/0aec339694a56e263d4b22475ff7211d40900830\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/7866116a040b3a23fb094e7d8f7ea3d61b3ac70b\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/b843a96252f672332837ea2ecb7c8db0acf68e20\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/c199ed687c00841daf60e9d131976958583a8c09\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/c5ef7228be04518d95591fc5369a9c554b19756d\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/e5e24a365a5e024efef63cc49abb345fbd4852c5\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/e64a48c50a1ff565a98c6a98d82b5b942868e76e\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-18T17:59:30+00:00",
      "cve": "CVE-2026-72253",
      "id": "CVE-2026-72253",
      "initial_release_date": "2026-08-15T00:00:00+00:00",
      "product_status:known_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: netfilter: nf_conntrack_sip: validate skb_dst() before accessing it",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-72253.json",
      "version": "3"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.