CVE-2026-74550 (GCVE-0-2026-74550)
Vulnerability from cvelistv5 – Published: 2026-08-15 12:27 – Updated: 2026-08-19 16:38
VLAI
EPSS
VEX
Title
net: do not send ICMP/NDISC Redirects when peer allocation fails
Summary
In the Linux kernel, the following vulnerability has been resolved:
net: do not send ICMP/NDISC Redirects when peer allocation fails
When inet_getpeer_v4() or inet_getpeer_v6() fails to allocate a peer entry
under memory pressure or tree size caps, redirect handlers previously fell
back to sending un-rate-limited ICMP/NDISC Redirect messages.
In IPv4, ip_rt_send_redirect() called icmp_send() directly when peer == NULL.
In IPv6, ip6_forward() and ndisc_send_redirect() passed a NULL peer into
inet_peer_xrlim_allow(), which returned true when peer == NULL.
Because ICMP/NDISC Redirects are not part of the default global rate limit
mask (sysctl_icmp_ratemask), sending redirects when peer == NULL creates
an un-rate-limited ICMP packet storm.
Fix this by failing closed in ip_rt_send_redirect(), ip6_forward(), and
ndisc_send_redirect() when peer is NULL.
Severity
7.5 (High)
Assigner
References
6 references
Impacted products
2 products
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Linux | Linux |
Affected:
92d8682926342d2b6aa5b2ecc02221e00e1573a0 , < c0adf8b4247bcc5a145a25c1929006eb392580bb
(git)
Affected: 92d8682926342d2b6aa5b2ecc02221e00e1573a0 , < f5ecaa7ea7686fa7ecdb6affc9d3a9a42e4524b1 (git) Affected: 92d8682926342d2b6aa5b2ecc02221e00e1573a0 , < 21666f7af49a90ef44d474916b8ef4402dfd74f5 (git) Affected: 92d8682926342d2b6aa5b2ecc02221e00e1573a0 , < 5ec5f00fc606a6df8434948c4552b3cb1176595d (git) Affected: 92d8682926342d2b6aa5b2ecc02221e00e1573a0 , < 828f6670d110ff2bf44c743037b38badc315704c (git) Affected: 92d8682926342d2b6aa5b2ecc02221e00e1573a0 , < dbc3791e3b2472e1ccc08947e0f83b443470ff4f (git) |
guessed | |
| Linux | Linux |
Affected:
2.6.39
Unaffected: 0 , < 2.6.39 (semver) Unaffected: 6.1.183 , ≤ 6.1.* (semver) Unaffected: 6.6.151 , ≤ 6.6.* (semver) Unaffected: 6.12.103 , ≤ 6.12.* (semver) Unaffected: 6.18.44 , ≤ 6.18.* (semver) Unaffected: 7.1.8 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix) |
guessed |
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"containers": {
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"programFiles": [
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},
{
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"version": "6.1.183",
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},
{
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"version": "6.6.151",
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{
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"version": "6.12.103",
"versionType": "semver"
},
{
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"status": "unaffected",
"version": "6.18.44",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.8",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.1.183",
"versionStartIncluding": "2.6.39",
"vulnerable": true
},
{
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{
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{
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}
],
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"operator": "OR"
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],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: do not send ICMP/NDISC Redirects when peer allocation fails\n\nWhen inet_getpeer_v4() or inet_getpeer_v6() fails to allocate a peer entry\nunder memory pressure or tree size caps, redirect handlers previously fell\nback to sending un-rate-limited ICMP/NDISC Redirect messages.\n\nIn IPv4, ip_rt_send_redirect() called icmp_send() directly when peer == NULL.\nIn IPv6, ip6_forward() and ndisc_send_redirect() passed a NULL peer into\ninet_peer_xrlim_allow(), which returned true when peer == NULL.\n\nBecause ICMP/NDISC Redirects are not part of the default global rate limit\nmask (sysctl_icmp_ratemask), sending redirects when peer == NULL creates\nan un-rate-limited ICMP packet storm.\n\nFix this by failing closed in ip_rt_send_redirect(), ip6_forward(), and\nndisc_send_redirect() when peer is NULL."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 7.5,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:N - The flaw is in IPv4/IPv6 packet forwarding paths (ip_forward/ip6_forward) reached when a remote host sends IP traffic processed by a forwarding router; this is standard net stack input handling, not a local-only API.\nAC:L - An attacker can reliably trigger redirect-eligible forwarded packets, flood unique source/destination addresses to stress inet_peer allocation, and induce memory pressure so peer allocation fails, controlling the conditions needed for the un-rate-limited redirect storm.\nPR:N - Exploitation requires only the ability to send IP packets to a forwarding host; no local account, capabilities, or authentication on the victim is needed.\nUI:N - No victim user action is required; the redirect storm is triggered entirely by attacker-sent network packets processed during kernel forwarding.\nS:U - Impact is confined to the kernel/network stack of the targeted forwarding system and its network availability; it does not cross VM, container, or IOMMU security boundaries.\nC:N - The bug bypasses redirect rate limiting to generate ICMP/NDISC storms; it does not involve memory corruption, out-of-bounds access, or unintended disclosure of sensitive kernel memory.\nI:N - The vulnerability causes excessive transmission of otherwise-valid redirect messages; it does not grant arbitrary data modification, code execution, or attacker-controlled corruption of kernel or application state.\nA:H - When peer allocation fails, ICMP/NDISC Redirects are sent without any rate limit (excluded from sysctl_icmp_ratemask), enabling a sustained packet storm that can exhaust CPU, memory, and bandwidth and deny service to the router and adjacent networks."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-19T16:38:44.870Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
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"url": "https://git.kernel.org/stable/c/c0adf8b4247bcc5a145a25c1929006eb392580bb"
},
{
"url": "https://git.kernel.org/stable/c/f5ecaa7ea7686fa7ecdb6affc9d3a9a42e4524b1"
},
{
"url": "https://git.kernel.org/stable/c/21666f7af49a90ef44d474916b8ef4402dfd74f5"
},
{
"url": "https://git.kernel.org/stable/c/5ec5f00fc606a6df8434948c4552b3cb1176595d"
},
{
"url": "https://git.kernel.org/stable/c/828f6670d110ff2bf44c743037b38badc315704c"
},
{
"url": "https://git.kernel.org/stable/c/dbc3791e3b2472e1ccc08947e0f83b443470ff4f"
}
],
"title": "net: do not send ICMP/NDISC Redirects when peer allocation fails",
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"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-74550",
"datePublished": "2026-08-15T12:27:57.615Z",
"dateReserved": "2026-08-15T05:44:03.915Z",
"dateUpdated": "2026-08-19T16:38:44.870Z",
"state": "PUBLISHED"
},
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"vulnerability-lookup:meta": {
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"cve": "CVE-2026-74550",
"date": "2026-10-13",
"epss": "0.00479",
"percentile": "0.39593"
},
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"cve": "CVE-2026-74550",
"id": "msrc_CVE-2026-74550",
"initial_release_date": "2026-08-23T15:01:55.000Z",
"product_status:fixed": "1",
"product_status:known_affected": "1",
"source": "Microsoft CSAF VEX",
"status": "final",
"title": "net: do not send ICMP/NDISC Redirects when peer allocation fails",
"url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-74550.json",
"version": "3"
},
"nvd": {
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"vendor": "Linux",
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"cveTags": [],
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"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: do not send ICMP/NDISC Redirects when peer allocation fails\n\nWhen inet_getpeer_v4() or inet_getpeer_v6() fails to allocate a peer entry\nunder memory pressure or tree size caps, redirect handlers previously fell\nback to sending un-rate-limited ICMP/NDISC Redirect messages.\n\nIn IPv4, ip_rt_send_redirect() called icmp_send() directly when peer == NULL.\nIn IPv6, ip6_forward() and ndisc_send_redirect() passed a NULL peer into\ninet_peer_xrlim_allow(), which returned true when peer == NULL.\n\nBecause ICMP/NDISC Redirects are not part of the default global rate limit\nmask (sysctl_icmp_ratemask), sending redirects when peer == NULL creates\nan un-rate-limited ICMP packet storm.\n\nFix this by failing closed in ip_rt_send_redirect(), ip6_forward(), and\nndisc_send_redirect() when peer is NULL."
}
],
"id": "CVE-2026-74550",
"lastModified": "2026-08-19T17:21:10.020",
"metrics": {
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{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 7.5,
"baseSeverity": "HIGH",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
},
"exploitabilityScore": 3.9,
"impactScore": 3.6,
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary"
}
]
},
"published": "2026-08-15T13:18:00.390",
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],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
},
"redhat_vex": {
"aggregate_severity": "Moderate",
"current_release_date": "2026-08-21T07:20:12+00:00",
"cve": "CVE-2026-74550",
"id": "CVE-2026-74550",
"initial_release_date": "2026-08-15T00:00:00+00:00",
"product_status:known_affected": "274",
"source": "Red Hat CSAF VEX",
"status": "final",
"title": "kernel: net: do not send ICMP/NDISC Redirects when peer allocation fails",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74550.json",
"version": "3"
}
}
}
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