CVE-2026-80792
Full vulnerability record from the local CVENow database.
Description
In the Linux kernel, the following vulnerability has been resolved: ipv6: fix use-after-free in ip6_finish_output2() ip6_finish_output2() caches a pointer to the IPv6 destination address (daddr) before invoking lwtunnel_xmit(). The LWT-BPF transmit path or other encapsulation operations within lwtunnel_xmit() can reallocate the skb head, freeing the memory that daddr points to. When lwtunnel_xmit() returns LWTUNNEL_XMIT_CONTINUE, the function continues to use the stale daddr pointer to compute the nexthop and to look up or create the neighbour entry. This results in a use-after-free read, which can leak sensitive kernel data, pollute the neighbour table with arbitrary values, misdirect traffic, or crash the system. Fix this by re-fetching the IPv6 header and the destination address pointer after lwtunnel_xmit() returns LWTUNNEL_XMIT_CONTINUE, ensuring that the subsequent nexthop computation and neighbour lookup operate on valid memory.
Severity
Not scored
CVSS score
Not available
Vulnerability status
Received
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-09-04 16:18:05.460000
Last modified
2026-10-19 09:17:13.330000
View original CVE JSON
{
"id": "CVE-2026-80792",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2026-09-04T16:18:05.460",
"lastModified": "2026-10-19T09:17:13.330",
"vulnStatus": "Received",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: fix use-after-free in ip6_finish_output2()\n\nip6_finish_output2() caches a pointer to the IPv6 destination\naddress (daddr) before invoking lwtunnel_xmit(). The LWT-BPF\ntransmit path or other encapsulation operations within\nlwtunnel_xmit() can reallocate the skb head, freeing the memory\nthat daddr points to. When lwtunnel_xmit() returns\nLWTUNNEL_XMIT_CONTINUE, the function continues to use the stale\ndaddr pointer to compute the nexthop and to look up or create the\nneighbour entry. This results in a use-after-free read, which can\nleak sensitive kernel data, pollute the neighbour table with\narbitrary values, misdirect traffic, or crash the system.\n\nFix this by re-fetching the IPv6 header and the destination\naddress pointer after lwtunnel_xmit() returns\nLWTUNNEL_XMIT_CONTINUE, ensuring that the subsequent nexthop\ncomputation and neighbour lookup operate on valid memory."
}
],
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "unaffected",
"programFiles": [
"net/ipv6/ip6_output.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
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"versionType": "git",
"status": "affected"
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{
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]
},
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "affected",
"programFiles": [
"net/ipv6/ip6_output.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "5.15",
"status": "affected"
},
{
"version": "0",
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"versionType": "semver",
"status": "unaffected"
},
{
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"lessThanOrEqual": "5.10.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "5.15.218",
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"status": "unaffected"
},
{
"version": "6.1.185",
"lessThanOrEqual": "6.1.*",
"versionType": "semver",
"status": "unaffected"
},
{
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"lessThanOrEqual": "6.6.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.12.106",
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"status": "unaffected"
},
{
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"lessThanOrEqual": "6.18.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "7.1.11",
"lessThanOrEqual": "7.1.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "7.2.1",
"lessThanOrEqual": "7.2.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "7.3",
"lessThanOrEqual": "*",
"versionType": "original_commit_for_fix",
"status": "unaffected"
}
]
}
]
}
],
"metrics": {},
"references": [
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}