CVE-2026-23247

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.

CVSS v3 5.5 MEDIUM

5.5^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 1.8 / Impact : 3.6

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://git.kernel.org/stable/c/025f532d8c5cfac77845e50daab7f478b360f2ac
https://git.kernel.org/stable/c/165573e41f2f66ef98940cf65f838b2cb575d9d1	Patch
https://git.kernel.org/stable/c/46e5b0d7cf55821527adea471ffe52a5afbd9caf	Patch
https://git.kernel.org/stable/c/5da5662181ef8a251e3ba564903002c2e87de452
https://git.kernel.org/stable/c/e873e8c16b2fb743a381a9e59c108e63512301ec
https://git.kernel.org/stable/c/eae2f14ab2efccdb7480fae7d42c4b0116ef8805	Patch

Configurations

Configuration 1 (hide)

OR	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel:4.10.14:::::::*
	cpe:2.3:o:linux:linux_kernel:4.11:-::::::
	cpe:2.3:o:linux:linux_kernel:4.11:rc6::::::
	cpe:2.3:o:linux:linux_kernel:4.11:rc7::::::
	cpe:2.3:o:linux:linux_kernel:4.11:rc8::::::
	cpe:2.3:o:linux:linux_kernel:7.0:rc1::::::
	cpe:2.3:o:linux:linux_kernel:7.0:rc2::::::

History

30 Oct 2026, 13:18

Type	Values Removed	Values Added
References		() https://git.kernel.org/stable/c/025f532d8c5cfac77845e50daab7f478b360f2ac -

21 Oct 2026, 13:18

Type	Values Removed	Values Added
References		() https://git.kernel.org/stable/c/e873e8c16b2fb743a381a9e59c108e63512301ec -

Information

Published : 2026-03-18 11:16

Updated : 2026-11-05 22:18

NVD link : CVE-2026-23247

Mitre link : CVE-2026-23247

CVE.ORG link : CVE-2026-23247

JSON object : View

Products Affected

linux

linux_kernel

CWE

NVD-CWE-noinfo

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"version": "443fac9f2618b93cbc5ab068dc594530236b3a23", "versionType": "git"}, {"status": "affected", "version": "4.10.14", "lessThan": "4.11", "versionType": "semver"}], "programFiles": ["include/net/secure_seq.h", "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"], "defaultStatus": "unaffected"}, {"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "4.11"}, {"status": "unaffected", "version": "0", "lessThan": "4.11", "versionType": "semver"}, {"status": "unaffected", "version": "6.1.191", "versionType": "semver", "lessThanOrEqual": "6.1.*"}, {"status": "unaffected", "version": "6.6.160", "versionType": "semver", "lessThanOrEqual": "6.6.*"}, {"status": "unaffected", "version": "6.12.94", "versionType": "semver", "lessThanOrEqual": "6.12.*"}, {"status": "unaffected", "version": "6.18.17", "versionType": "semver", "lessThanOrEqual": "6.18.*"}, {"status": "unaffected", "version": "6.19.7", "versionType": "semver", "lessThanOrEqual": "6.19.*"}, {"status": "unaffected", "version": "7.0", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*"}], "programFiles": ["include/net/secure_seq.h", "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"], "defaultStatus": "affected"}]}], "published": "2026-03-18T11:16:16.723", "references": [{"url": "https://git.kernel.org/stable/c/025f532d8c5cfac77845e50daab7f478b360f2ac", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/165573e41f2f66ef98940cf65f838b2cb575d9d1", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/46e5b0d7cf55821527adea471ffe52a5afbd9caf", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/5da5662181ef8a251e3ba564903002c2e87de452", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/e873e8c16b2fb743a381a9e59c108e63512301ec", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/eae2f14ab2efccdb7480fae7d42c4b0116ef8805", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "vulnStatus": "Modified", "weaknesses": [{"type": "Primary", "source": "nvd@nist.gov", "description": [{"lang": "en", "value": "NVD-CWE-noinfo"}]}], "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: a\u00f1adir 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 desapareci\u00f3 en 2017.\n\nZhouyan Deng inform\u00f3 de una fuga de puerto de origen TCP fuera de ruta a trav\u00e9s de un canal lateral de SYN cookie que se puede solucionar de m\u00faltiples maneras.\n\nUna de ellas es traer de vuelta los puertos TCP en la aleatorizaci\u00f3n del desplazamiento TS.\n\nComo ventaja adicional, realizamos un \u00fanico c\u00e1lculo de siphash() para proporcionar tanto un ISN como un desplazamiento TS."}], "lastModified": "2026-11-05T22:18:08.477", "configurations": [{"nodes": 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