{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-74747", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-15T05:44:03.931Z", "datePublished": "2026-08-26T14:36:56.563Z", "dateUpdated": "2026-08-27T05:01:08.455Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-27T05:01:08.455Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipvs: revalidate ihl to prevent out-of-bounds access\n\nWhile the outer IP header is already pulled into the skb head,\nwe must be careful and revalidate the embedded headers after\nreading them from the skb frags to prevent out-of-bounds\naccess.\n\nOne such place reported by Sashiko is ip_vs_nat_icmp() where\nlocal process can change the ihl field and after\nskb_ensure_writable() we can see larger value which is a\nproblem for the ip_send_check(cih) calls.\n\nAdd check to drop the packet if the ihl field is changed."}], "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 - Exploitation requires a local process to TOCTOU-modify the embedded IPv4 ihl in skb frags between ip_vs_fill_iph_skb_icmp() and skb_ensure_writable(); remote ICMP to IPVS NAT hooks reaches ip_vs_nat_icmp() but cannot change skb backing memory without local access to the packet buffer.\nAC:L - A local attacker controls both sides of the race by concurrently injecting ICMP errors matching an IPVS NAT connection and mutating the embedded header ihl in userspace-backed skb frags during softirq processing; no uncontrollable victim state or heap layout is required.\nPR:L - Only a local account able to race skb frag modification (e.g., via raw/packet sockets with CAP_NET_RAW obtainable in user namespaces) against IPVS ICMP NAT handling on a host where IPVS is already configured is needed; init-namespace root is not required.\nUI:N - No victim user interaction is required; exploitation is driven entirely by attacker-controlled local packet injection and concurrent frag modification while IPVS processes ICMP errors on NAT-mode connections through LOCAL_IN, LOCAL_OUT, or FORWARD hooks.\nS:U - The out-of-bounds access corrupts kernel skb memory on the IPVS load-balancer host within the same kernel security authority; it does not cross VM, container, or IOMMU boundaries into a separate security scope.\nC:H - After skb_ensure_writable(), ip_send_check(cih) re-reads an attacker-inflated cih->ihl and ip_fast_csum() reads far beyond the validated skb region, enabling out-of-bounds kernel memory disclosure on internet-facing IPVS NAT nodes and kube-proxy IPVS clusters.\nI:H - The inflated ihl causes out-of-bounds access during ICMP NAT mangling in ip_vs_nat_icmp(), corrupting skb data beyond skb_ensure_writable()'s bound; such kernel memory corruption is exploitable for control-flow hijacking and privilege escalation on load balancers.\nA:H - Out-of-bounds access in ip_send_check(cih) during ICMP NAT handling can trigger kernel oops or panic; a local attacker can repeatedly race the TOCTOU on IPVS NAT nodes, causing sustained denial of service on critical infrastructure."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["include/net/ip_vs.h", "net/netfilter/ipvs/ip_vs_core.c", "net/netfilter/ipvs/ip_vs_xmit.c"], "versions": [{"version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "5365f012451fce2453f13a568dcb72ea534c1e4d", "status": "affected", "versionType": "git"}, {"version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "d93660df4dd1d116f608ada4a29a80a5d6f0a6ed", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["include/net/ip_vs.h", "net/netfilter/ipvs/ip_vs_core.c", "net/netfilter/ipvs/ip_vs_xmit.c"], "versions": [{"version": "2.6.12", "status": "affected"}, {"version": "0", "lessThan": "2.6.12", "status": "unaffected", "versionType": "semver"}, {"version": "7.1.10", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2", "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": "2.6.12", "versionEndExcluding": "7.1.10"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "7.2"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/5365f012451fce2453f13a568dcb72ea534c1e4d"}, {"url": "https://git.kernel.org/stable/c/d93660df4dd1d116f608ada4a29a80a5d6f0a6ed"}], "title": "ipvs: revalidate ihl to prevent out-of-bounds access", "x_generator": {"engine": "bippy-1.2.0"}}}}

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{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["include/net/ip_vs.h", "net/netfilter/ipvs/ip_vs_core.c", "net/netfilter/ipvs/ip_vs_xmit.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "5365f012451fce2453f13a568dcb72ea534c1e4d", "status": "affected", "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "versionType": "git"}, {"lessThan": "d93660df4dd1d116f608ada4a29a80a5d6f0a6ed", "status": "affected", "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["include/net/ip_vs.h", "net/netfilter/ipvs/ip_vs_core.c", "net/netfilter/ipvs/ip_vs_xmit.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "2.6.12"}, {"lessThan": "2.6.12", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "7.1.*", "status": "unaffected", "version": "7.1.10", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.2", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipvs: revalidate ihl to prevent out-of-bounds access\n\nWhile the outer IP header is already pulled into the skb head,\nwe must be careful and revalidate the embedded headers after\nreading them from the skb frags to prevent out-of-bounds\naccess.\n\nOne such place reported by Sashiko is ip_vs_nat_icmp() where\nlocal process can change the ihl field and after\nskb_ensure_writable() we can see larger value which is a\nproblem for the ip_send_check(cih) calls.\n\nAdd check to drop the packet if the ihl field is changed."}], "id": "CVE-2026-74747", "lastModified": "2026-08-27T06:17:25.410", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-08-26T15:16:53.657", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/5365f012451fce2453f13a568dcb72ea534c1e4d"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/d93660df4dd1d116f608ada4a29a80a5d6f0a6ed"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: ipvs: revalidate ihl to prevent out-of-bounds access", "id": "2524481", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2524481"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.5", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-125", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nipvs: revalidate ihl to prevent out-of-bounds access\nWhile the outer IP header is already pulled into the skb head,\nwe must be careful and revalidate the embedded headers after\nreading them from the skb frags to prevent out-of-bounds\naccess.\nOne such place reported by Sashiko is ip_vs_nat_icmp() where\nlocal process can change the ihl field and after\nskb_ensure_writable() we can see larger value which is a\nproblem for the ip_send_check(cih) calls.\nAdd check to drop the packet if the ihl field is changed.", "A flaw was found in the Linux kernel's IP Virtual Server (IPVS) component. A local attacker can manipulate the IP Header Length (ihl) field within network packets. This manipulation can lead to an out-of-bounds access when the kernel attempts to revalidate embedded headers, potentially causing system instability or a denial of service."], "name": "CVE-2026-74747", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Out of support scope", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Fix deferred", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-08-26T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-74747\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-74747\nhttps://lore.kernel.org/linux-cve-announce/2026082658-CVE-2026-74747-32a0@gregkh/T"], "threat_severity": "Moderate"}