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TI-2026-45986 Aliases CVE-2026-64422GHSA-gwmg-q555-3325

net: ipv4: bound TCP reordering sysctl writes and MTU probe sizes

Priority LOW 30CWE-190Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
High · None · High
Fix status
Partial Red Hat: 5 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.

Summary

In the Linux kernel, the following vulnerability has been resolved: net: ipv4: bound TCP reordering sysctl writes and MTU probe sizes Reject invalid `net.ipv4.tcp_reordering` values before they reach TCP socket state. The sysctl is stored as an `int` but copied into the `u32` `tp->reordering` field for new sockets, so negative writes wrap to large values. With `tcp_mtu_probing=2`, the wrapped value can overflow the `tcp_mtu_probe()` size calculation and drive the MTU probing path into an out-of-bounds read. Route `tcp_reordering` writes through `proc_dointvec_minmax()` and require it to be at least 1. Also require `tcp_max_reordering` to be at least 1 so the configured maximum cannot become negative either. When registering the table for a non-init network namespace, relocate `extra2` pointers that refer into `init_net.ipv4` so the `tcp_reordering` upper bound follows that namespace's `tcp_max_reordering`. Harden `tcp_mtu_probe()` itself by computing `size_needed` as `u64`. This keeps the send queue and window checks from being bypassed through signed integer overflow.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00138 3rd percentileScored 2026-11-07
Fix Partial Linux (Linux): 5.10.261, 5.15.212, 6.1.178 +5Red Hat: 5 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
LinuxLinux2.6.24 and later5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.96, 6.18.39, 7.1.4, 7.2Patch availableCNA
  • Linux VendorLinux Affected 2.6.24 and later Fixed in 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.96, 6.18.39, 7.1.4, 7.2 Patch available CNA

CPE configurations NVD · 7

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*2.6.24.1 to before 5.10.261; 5.11 to before 5.15.212; 5.16 to before 6.1.178; 6.2 to before 6.6.145; 6.7 to before 6.12.96; 6.13 to before 6.18.39; 6.19 to before 7.1.4VulnerableLinux
cpe:2.3:o:linux:linux_kernel:2.6.24:-:*:*:*:*:*:*2.6.24VulnerableLinux
cpe:2.3:o:linux:linux_kernel:2.6.24:rc4:*:*:*:*:*:*2.6.24 rc4VulnerableLinux
cpe:2.3:o:linux:linux_kernel:2.6.24:rc5:*:*:*:*:*:*2.6.24 rc5VulnerableLinux
cpe:2.3:o:linux:linux_kernel:2.6.24:rc6:*:*:*:*:*:*2.6.24 rc6VulnerableLinux
cpe:2.3:o:linux:linux_kernel:2.6.24:rc7:*:*:*:*:*:*2.6.24 rc7VulnerableLinux
cpe:2.3:o:linux:linux_kernel:2.6.24:rc8:*:*:*:*:*:*2.6.24 rc8VulnerableLinux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 2.6.24.1 to before 5.10.261; 5.11 to before 5.15.212; 5.16 to before 6.1.178; 6.2 to before 6.6.145; 6.7 to before 6.12.96; 6.13 to before 6.18.39; 6.19 to before 7.1.4 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:2.6.24:-:*:*:*:*:*:* Versions 2.6.24 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:2.6.24:rc4:*:*:*:*:*:* Versions 2.6.24 rc4 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:2.6.24:rc5:*:*:*:*:*:* Versions 2.6.24 rc5 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:2.6.24:rc6:*:*:*:*:*:* Versions 2.6.24 rc6 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:2.6.24:rc7:*:*:*:*:*:* Versions 2.6.24 rc7 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:2.6.24:rc8:*:*:*:*:*:* Versions 2.6.24 rc8 Vulnerable ·Linux

Remediation

  • Fix · CNA Linux (Linux) Fixed in 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.96, 6.18.39, 7.1.4, 7.2

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 10AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 6AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 7AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 8AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 9AffectedNo fix yet: Fix deferred

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-64422
  2. 2026-10-03 Alias added: GHSA-gwmg-q555-3325
  3. 2026-10-16 CISA SSVC decision points changed
  4. 2026-10-20 Weakness changed · CISA ADP
  5. 2026-10-27 CVSS score changed · Red Hat
  6. 2026-11-06 Affected versions changed · Red Hat

References

Patch 8

  • TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
  • TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
  • TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
  • TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
  • TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
  • TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
See all 15278 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences