CVE-2026-23247
Full vulnerability record from the local CVENow database.
Description
In the Linux kernel, the following vulnerability has been resolved: tcp: secure_seq: add back ports to TS offset This reverts 28ee1b746f49 ("secure_seq: downgrade to per-host timestamp offsets") tcp_tw_recycle went away in 2017. Zhouyan Deng reported off-path TCP source port leakage via SYN cookie side-channel that can be fixed in multiple ways. One of them is to bring back TCP ports in TS offset randomization. As a bonus, we perform a single siphash() computation to provide both an ISN and a TS offset.
Severity
MEDIUM
CVSS score
5.5
(v3.1)
Vulnerability status
Modified
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-03-18 11:16:16.723000
Last modified
2026-10-30 13:18:35.117000
View original CVE JSON
{
"id": "CVE-2026-23247",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2026-03-18T11:16:16.723",
"lastModified": "2026-10-30T13:18:35.117",
"vulnStatus": "Modified",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntcp: secure_seq: add back ports to TS offset\n\nThis reverts 28ee1b746f49 (\"secure_seq: downgrade to per-host timestamp offsets\")\n\ntcp_tw_recycle went away in 2017.\n\nZhouyan Deng reported off-path TCP source port leakage via\nSYN cookie side-channel that can be fixed in multiple ways.\n\nOne of them is to bring back TCP ports in TS offset randomization.\n\nAs a bonus, we perform a single siphash() computation\nto provide both an ISN and a TS offset."
},
{
"lang": "es",
"value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\ntcp: secure_seq: añadir de nuevo puertos al desplazamiento TS\n\nEsto revierte 28ee1b746f49 ('secure_seq: degradar a desplazamientos de marca de tiempo por host')\n\ntcp_tw_recycle desapareció en 2017.\n\nZhouyan Deng informó de una fuga de puerto de origen TCP fuera de ruta a través de un canal lateral de SYN cookie que se puede solucionar de múltiples maneras.\n\nUna de ellas es traer de vuelta los puertos TCP en la aleatorización del desplazamiento TS.\n\nComo ventaja adicional, realizamos un único cálculo de siphash() para proporcionar tanto un ISN como un desplazamiento TS."
}
],
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"net/ipv4/syncookies.c",
"net/ipv4/tcp_input.c",
"net/ipv4/tcp_ipv4.c",
"net/ipv6/syncookies.c",
"net/ipv6/tcp_ipv6.c"
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"include/net/tcp.h",
"net/core/secure_seq.c",
"net/ipv4/syncookies.c",
"net/ipv4/tcp_input.c",
"net/ipv4/tcp_ipv4.c",
"net/ipv6/syncookies.c",
"net/ipv6/tcp_ipv6.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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"versionType": "original_commit_for_fix",
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],
"metrics": {
"cvssMetricV31": [
{
"source": "[email protected]",
"type": "Primary",
"cvssData": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"baseScore": 5.5,
"baseSeverity": "MEDIUM",
"attackVector": "LOCAL",
"attackComplexity": "LOW",
"privilegesRequired": "LOW",
"userInteraction": "NONE",
"scope": "UNCHANGED",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"availabilityImpact": "HIGH"
},
"exploitabilityScore": 1.8,
"impactScore": 3.6
}
]
},
"weaknesses": [
{
"source": "[email protected]",
"type": "Primary",
"description": [
{
"lang": "en",
"value": "NVD-CWE-noinfo"
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"configurations": [
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