{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-80978", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-26T14:34:25.811Z", "datePublished": "2026-09-11T19:42:39.496Z", "dateUpdated": "2026-09-11T19:42:39.496Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-09-11T19:42:39.496Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: cap advertised IP tunnel headroom\n\nIP tunnel devices derive their advertised needed_headroom from lower\noutput devices. A stack of user-created devices can make the derived\nvalue larger than the 16-bit skb header offsets can represent. Once IP\noutput reserves it, skb head expansion can wrap those offsets.\n\nThe runtime transmit path already caps a growing needed_headroom at 512.\nApply the same cap when tunnel configuration publishes needed_headroom\nderived from a lower output device.\n\nCapping the advertised value is safe: IP tunnel transmit still expands\nthe skb when a packet needs more headroom. A nonsensical stacked\nconfiguration can therefore incur an extra reallocation, but it cannot\npublish an unbounded reservation to upper layers."}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["include/net/ip_tunnels.h", "net/ipv4/ip_tunnel.c", "net/ipv6/ip6_gre.c", "net/ipv6/ip6_tunnel.c", "net/ipv6/sit.c"], "versions": [{"version": "1a37e412a0225fcba5587f24c0dfc7636efc8b69", "lessThan": "bc4e05ae66c9797a0972ac44326e69c5305e0020", "status": "affected", "versionType": "git"}, {"version": "1a37e412a0225fcba5587f24c0dfc7636efc8b69", "lessThan": "af0ee8f04bea22cdb331fa3509e17f81b48938ad", "status": "affected", "versionType": "git"}, {"version": "1a37e412a0225fcba5587f24c0dfc7636efc8b69", "lessThan": "9144f2c53a04465a6878172b523f640313c5559e", "status": "affected", "versionType": "git"}, {"version": "1a37e412a0225fcba5587f24c0dfc7636efc8b69", "lessThan": "6b222adeb9340306e2ff97127c76117abb9b3df8", "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_tunnels.h", "net/ipv4/ip_tunnel.c", "net/ipv6/ip6_gre.c", "net/ipv6/ip6_tunnel.c", "net/ipv6/sit.c"], "versions": [{"version": "3.11", "status": "affected"}, {"version": "0", "lessThan": "3.11", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.109", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.50", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2.4", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.3-rc1", "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": "3.11", "versionEndExcluding": "6.12.109"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.11", "versionEndExcluding": "6.18.50"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.11", "versionEndExcluding": "7.2.4"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.11", "versionEndExcluding": "7.3-rc1"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/bc4e05ae66c9797a0972ac44326e69c5305e0020"}, {"url": "https://git.kernel.org/stable/c/af0ee8f04bea22cdb331fa3509e17f81b48938ad"}, {"url": "https://git.kernel.org/stable/c/9144f2c53a04465a6878172b523f640313c5559e"}, {"url": "https://git.kernel.org/stable/c/6b222adeb9340306e2ff97127c76117abb9b3df8"}], "title": "net: cap advertised IP tunnel headroom", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["include/net/ip_tunnels.h", "net/ipv4/ip_tunnel.c", "net/ipv6/ip6_gre.c", "net/ipv6/ip6_tunnel.c", "net/ipv6/sit.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "bc4e05ae66c9797a0972ac44326e69c5305e0020", "status": "affected", "version": "1a37e412a0225fcba5587f24c0dfc7636efc8b69", "versionType": "git"}, {"lessThan": "af0ee8f04bea22cdb331fa3509e17f81b48938ad", "status": "affected", "version": "1a37e412a0225fcba5587f24c0dfc7636efc8b69", "versionType": "git"}, {"lessThan": "9144f2c53a04465a6878172b523f640313c5559e", "status": "affected", "version": "1a37e412a0225fcba5587f24c0dfc7636efc8b69", "versionType": "git"}, {"lessThan": "6b222adeb9340306e2ff97127c76117abb9b3df8", "status": "affected", "version": "1a37e412a0225fcba5587f24c0dfc7636efc8b69", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["include/net/ip_tunnels.h", "net/ipv4/ip_tunnel.c", "net/ipv6/ip6_gre.c", "net/ipv6/ip6_tunnel.c", "net/ipv6/sit.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "3.11"}, {"lessThan": "3.11", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.109", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.50", "versionType": "semver"}, {"lessThanOrEqual": "7.2.*", "status": "unaffected", "version": "7.2.4", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.3-rc1", "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\nnet: cap advertised IP tunnel headroom\n\nIP tunnel devices derive their advertised needed_headroom from lower\noutput devices. A stack of user-created devices can make the derived\nvalue larger than the 16-bit skb header offsets can represent. Once IP\noutput reserves it, skb head expansion can wrap those offsets.\n\nThe runtime transmit path already caps a growing needed_headroom at 512.\nApply the same cap when tunnel configuration publishes needed_headroom\nderived from a lower output device.\n\nCapping the advertised value is safe: IP tunnel transmit still expands\nthe skb when a packet needs more headroom. A nonsensical stacked\nconfiguration can therefore incur an extra reallocation, but it cannot\npublish an unbounded reservation to upper layers."}], "id": "CVE-2026-80978", "lastModified": "2026-09-11T20:19:04.143", "metrics": {}, "published": "2026-09-11T20:19:04.143", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/6b222adeb9340306e2ff97127c76117abb9b3df8"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/9144f2c53a04465a6878172b523f640313c5559e"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/af0ee8f04bea22cdb331fa3509e17f81b48938ad"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/bc4e05ae66c9797a0972ac44326e69c5305e0020"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: Linux kernel: IP tunnel headroom miscalculation can lead to network performance degradation", "id": "2532487", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2532487"}, "csaw": false, "cvss3": {"cvss3_base_score": "4.1", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-190", "details": ["A flaw was found in the Linux kernel, specifically within its IP tunnel devices. A local attacker could create a stack of user-controlled IP tunnel devices, causing the system to miscalculate the required memory for network packet headers. This miscalculation can lead to unnecessary memory reallocations during packet transmission, which may result in performance degradation for network operations."], "name": "CVE-2026-80978", "public_date": "2026-09-11T19:42:39Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-80978\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-80978\nhttps://git.kernel.org/stable/c/6b222adeb9340306e2ff97127c76117abb9b3df8\nhttps://git.kernel.org/stable/c/9144f2c53a04465a6878172b523f640313c5559e\nhttps://git.kernel.org/stable/c/af0ee8f04bea22cdb331fa3509e17f81b48938ad\nhttps://git.kernel.org/stable/c/bc4e05ae66c9797a0972ac44326e69c5305e0020"], "threat_severity": "Moderate"}

{}