9.8
CRITICAL CVSS 3.1
CVE-2026-72020
ipvs: reset full ip_vs_seq structs in ip_vs_conn_new
Description

In the Linux kernel, the following vulnerability has been resolved: ipvs: reset full ip_vs_seq structs in ip_vs_conn_new Commit 9a05475cebdd ("ipvs: avoid kmem_cache_zalloc in ip_vs_conn_new") changed ip_vs_conn_new() to allocate an ip_vs_conn object with kmem_cache_alloc(). The function then initializes many fields explicitly, but only resets in_seq.delta and out_seq.delta in the two struct ip_vs_seq members. That leaves init_seq and previous_delta uninitialized. This is normally harmless while the corresponding IP_VS_CONN_F_IN_SEQ or IP_VS_CONN_F_OUT_SEQ flag is clear. For connections learned from a sync message, however, ip_vs_proc_conn() preserves those flags from IP_VS_CONN_F_BACKUP_MASK and passes opt=NULL when the message omits IPVS_OPT_SEQ_DATA. In that case the new connection can be hashed with SEQ flags set but with the rest of in_seq/out_seq still containing stale slab data. When a packet for such a connection is later handled by an IPVS application helper, vs_fix_seq() and vs_fix_ack_seq() use previous_delta and init_seq to rewrite TCP sequence numbers. A malformed sync message can therefore make forwarded packets carry stale slab bytes in their TCP seq/ack numbers, and can also corrupt the forwarded TCP flow. Reset both struct ip_vs_seq members completely before publishing the connection. This matches the existing "reset struct ip_vs_seq" comment and keeps the sequence-adjustment gates inactive unless valid sequence data is installed later.

INFO

Published Date :

Aug. 15, 2026, 6:21 a.m.

Last Modified :

Aug. 17, 2026, 6:17 a.m.

Remotely Exploit :

Yes !

Source :

416baaa9-dc9f-4396-8d5f-8c081fb06d67
Affected Products

The following products are affected by CVE-2026-72020 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Linux linux_kernel
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 CRITICAL 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
Ensure all struct ip_vs_seq members are reset before publishing connections.
  • Reset both struct ip_vs_seq members completely.
  • Ensure sequence-adjustment gates are inactive unless valid data is installed.
  • Apply kernel patches or updates that address this issue.
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-72020 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-72020 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-72020 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2026-72020 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Aug. 17, 2026

    Action Type Old Value New Value
    Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    Changed Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '9a05475cebdd6341884b5901e53870be26e65158', 'lessThan': '3bf9a260188b2a5449cbddc032a749ab433fe328', 'versionType': 'git'}, {'status': 'affected', 'version': '9a05475cebdd6341884b5901e53870be26e65158', 'lessThan': '6378c5cb360eb1750f88839d7c3613ea92ac1816', 'versionType': 'git'}, {'status': 'affected', 'version': '9a05475cebdd6341884b5901e53870be26e65158', 'lessThan': '32c299e28b8eea6cbbd23b97dc61401e9ef9c445', 'versionType': 'git'}, {'status': 'affected', 'version': '9a05475cebdd6341884b5901e53870be26e65158', 'lessThan': '9e36602cbec552286f7e691cfd366525c565ee74', 'versionType': 'git'}, {'status': 'affected', 'version': '9a05475cebdd6341884b5901e53870be26e65158', 'lessThan': 'd0eed7177e822cab83141e5c44b2aa345c7fd379', 'versionType': 'git'}, {'status': 'affected', 'version': '9a05475cebdd6341884b5901e53870be26e65158', 'lessThan': '83fb4c2c5344f02eac929f66de3c9d1adfcde04c', 'versionType': 'git'}, {'status': 'affected', 'version': '9a05475cebdd6341884b5901e53870be26e65158', 'lessThan': '6335ab62d5fc9ed875279238233fba3462c168f5', 'versionType': 'git'}, {'status': 'affected', 'version': '9a05475cebdd6341884b5901e53870be26e65158', 'lessThan': '2975324d164c552b028632f107b567302863b7f6', 'versionType': 'git'}], 'programFiles': ['net/netfilter/ipvs/ip_vs_conn.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '3.10'}, {'status': 'unaffected', 'version': '0', 'lessThan': '3.10', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '5.10.261', 'versionType': 'semver', 'lessThanOrEqual': '5.10.*'}, {'status': 'unaffected', 'version': '5.15.212', 'versionType': 'semver', 'lessThanOrEqual': '5.15.*'}, {'status': 'unaffected', 'version': '6.1.178', 'versionType': 'semver', 'lessThanOrEqual': '6.1.*'}, {'status': 'unaffected', 'version': '6.6.145', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.97', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.40', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.5', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc3', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/netfilter/ipvs/ip_vs_conn.c'], 'defaultStatus': 'affected'}] [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '9a05475cebdd6341884b5901e53870be26e65158', 'lessThan': '3bf9a260188b2a5449cbddc032a749ab433fe328', 'versionType': 'git'}, {'status': 'affected', 'version': '9a05475cebdd6341884b5901e53870be26e65158', 'lessThan': '6378c5cb360eb1750f88839d7c3613ea92ac1816', 'versionType': 'git'}, {'status': 'affected', 'version': '9a05475cebdd6341884b5901e53870be26e65158', 'lessThan': '32c299e28b8eea6cbbd23b97dc61401e9ef9c445', 'versionType': 'git'}, {'status': 'affected', 'version': '9a05475cebdd6341884b5901e53870be26e65158', 'lessThan': '9e36602cbec552286f7e691cfd366525c565ee74', 'versionType': 'git'}, {'status': 'affected', 'version': '9a05475cebdd6341884b5901e53870be26e65158', 'lessThan': 'd0eed7177e822cab83141e5c44b2aa345c7fd379', 'versionType': 'git'}, {'status': 'affected', 'version': '9a05475cebdd6341884b5901e53870be26e65158', 'lessThan': '83fb4c2c5344f02eac929f66de3c9d1adfcde04c', 'versionType': 'git'}, {'status': 'affected', 'version': '9a05475cebdd6341884b5901e53870be26e65158', 'lessThan': '6335ab62d5fc9ed875279238233fba3462c168f5', 'versionType': 'git'}, {'status': 'affected', 'version': '9a05475cebdd6341884b5901e53870be26e65158', 'lessThan': '2975324d164c552b028632f107b567302863b7f6', 'versionType': 'git'}], 'programFiles': ['net/netfilter/ipvs/ip_vs_conn.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '3.10'}, {'status': 'unaffected', 'version': '0', 'lessThan': '3.10', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '5.10.261', 'versionType': 'semver', 'lessThanOrEqual': '5.10.*'}, {'status': 'unaffected', 'version': '5.15.212', 'versionType': 'semver', 'lessThanOrEqual': '5.15.*'}, {'status': 'unaffected', 'version': '6.1.178', 'versionType': 'semver', 'lessThanOrEqual': '6.1.*'}, {'status': 'unaffected', 'version': '6.6.145', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.97', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.40', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.5', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/netfilter/ipvs/ip_vs_conn.c'], 'defaultStatus': 'affected'}]
  • New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Aug. 15, 2026

    Action Type Old Value New Value
    Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '9a05475cebdd6341884b5901e53870be26e65158', 'lessThan': '3bf9a260188b2a5449cbddc032a749ab433fe328', 'versionType': 'git'}, {'status': 'affected', 'version': '9a05475cebdd6341884b5901e53870be26e65158', 'lessThan': '6378c5cb360eb1750f88839d7c3613ea92ac1816', 'versionType': 'git'}, {'status': 'affected', 'version': '9a05475cebdd6341884b5901e53870be26e65158', 'lessThan': '32c299e28b8eea6cbbd23b97dc61401e9ef9c445', 'versionType': 'git'}, {'status': 'affected', 'version': '9a05475cebdd6341884b5901e53870be26e65158', 'lessThan': '9e36602cbec552286f7e691cfd366525c565ee74', 'versionType': 'git'}, {'status': 'affected', 'version': '9a05475cebdd6341884b5901e53870be26e65158', 'lessThan': 'd0eed7177e822cab83141e5c44b2aa345c7fd379', 'versionType': 'git'}, {'status': 'affected', 'version': '9a05475cebdd6341884b5901e53870be26e65158', 'lessThan': '83fb4c2c5344f02eac929f66de3c9d1adfcde04c', 'versionType': 'git'}, {'status': 'affected', 'version': '9a05475cebdd6341884b5901e53870be26e65158', 'lessThan': '6335ab62d5fc9ed875279238233fba3462c168f5', 'versionType': 'git'}, {'status': 'affected', 'version': '9a05475cebdd6341884b5901e53870be26e65158', 'lessThan': '2975324d164c552b028632f107b567302863b7f6', 'versionType': 'git'}], 'programFiles': ['net/netfilter/ipvs/ip_vs_conn.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '3.10'}, {'status': 'unaffected', 'version': '0', 'lessThan': '3.10', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '5.10.261', 'versionType': 'semver', 'lessThanOrEqual': '5.10.*'}, {'status': 'unaffected', 'version': '5.15.212', 'versionType': 'semver', 'lessThanOrEqual': '5.15.*'}, {'status': 'unaffected', 'version': '6.1.178', 'versionType': 'semver', 'lessThanOrEqual': '6.1.*'}, {'status': 'unaffected', 'version': '6.6.145', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.97', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.40', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.5', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc3', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/netfilter/ipvs/ip_vs_conn.c'], 'defaultStatus': 'affected'}]
    Added Description In the Linux kernel, the following vulnerability has been resolved: ipvs: reset full ip_vs_seq structs in ip_vs_conn_new Commit 9a05475cebdd ("ipvs: avoid kmem_cache_zalloc in ip_vs_conn_new") changed ip_vs_conn_new() to allocate an ip_vs_conn object with kmem_cache_alloc(). The function then initializes many fields explicitly, but only resets in_seq.delta and out_seq.delta in the two struct ip_vs_seq members. That leaves init_seq and previous_delta uninitialized. This is normally harmless while the corresponding IP_VS_CONN_F_IN_SEQ or IP_VS_CONN_F_OUT_SEQ flag is clear. For connections learned from a sync message, however, ip_vs_proc_conn() preserves those flags from IP_VS_CONN_F_BACKUP_MASK and passes opt=NULL when the message omits IPVS_OPT_SEQ_DATA. In that case the new connection can be hashed with SEQ flags set but with the rest of in_seq/out_seq still containing stale slab data. When a packet for such a connection is later handled by an IPVS application helper, vs_fix_seq() and vs_fix_ack_seq() use previous_delta and init_seq to rewrite TCP sequence numbers. A malformed sync message can therefore make forwarded packets carry stale slab bytes in their TCP seq/ack numbers, and can also corrupt the forwarded TCP flow. Reset both struct ip_vs_seq members completely before publishing the connection. This matches the existing "reset struct ip_vs_seq" comment and keeps the sequence-adjustment gates inactive unless valid sequence data is installed later.
    Added Reference https://git.kernel.org/stable/c/2975324d164c552b028632f107b567302863b7f6
    Added Reference https://git.kernel.org/stable/c/32c299e28b8eea6cbbd23b97dc61401e9ef9c445
    Added Reference https://git.kernel.org/stable/c/3bf9a260188b2a5449cbddc032a749ab433fe328
    Added Reference https://git.kernel.org/stable/c/6335ab62d5fc9ed875279238233fba3462c168f5
    Added Reference https://git.kernel.org/stable/c/6378c5cb360eb1750f88839d7c3613ea92ac1816
    Added Reference https://git.kernel.org/stable/c/83fb4c2c5344f02eac929f66de3c9d1adfcde04c
    Added Reference https://git.kernel.org/stable/c/9e36602cbec552286f7e691cfd366525c565ee74
    Added Reference https://git.kernel.org/stable/c/d0eed7177e822cab83141e5c44b2aa345c7fd379
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.