tcp: secure_seq: add back ports to TS offset
Priority LOW 24Published · Updated
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 4 without a fix
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat.
Summary
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.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00171 6th percentileScored 2026-11-07
Fix Partial Linux (Linux): 4.11, 6.1.191, 6.6.160 +4Red Hat: 4 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
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 4.10.14 to before 4.11 | 4.11 | Patch available | CNA |
| Linux | Linux | 4.11 and later | 6.1.191, 6.6.160, 6.12.94, 6.18.17, 6.19.7, 7.0 | Patch available | CNA |
- Linux VendorLinux Affected 4.10.14 to before 4.11 Fixed in 4.11 Patch available CNA
- Linux VendorLinux Affected 4.11 and later Fixed in 6.1.191, 6.6.160, 6.12.94, 6.18.17, 6.19.7, 7.0 Patch available CNA
CPE configurations NVD · 8
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | after 4.11, before 6.18.17; 6.19 to before 6.19.7 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:4.10.14:*:*:*:*:*:*:* | 4.10.14 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:4.11:-:*:*:*:*:*:* | 4.11 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:4.11:rc6:*:*:*:*:*:* | 4.11 rc6 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:4.11:rc7:*:*:*:*:*:* | 4.11 rc7 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:4.11:rc8:*:*:*:*:*:* | 4.11 rc8 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:* | 7.0 rc1 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:* | 7.0 rc2 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions after 4.11, before 6.18.17; 6.19 to before 6.19.7 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:4.10.14:*:*:*:*:*:*:* Versions 4.10.14 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:4.11:-:*:*:*:*:*:* Versions 4.11 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:4.11:rc6:*:*:*:*:*:* Versions 4.11 rc6 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:4.11:rc7:*:*:*:*:*:* Versions 4.11 rc7 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:4.11:rc8:*:*:*:*:*:* Versions 4.11 rc8 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:* Versions 7.0 rc1 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:* Versions 7.0 rc2 Vulnerable ·Linux
Remediation
- Fix · CNA Linux (Linux) Fixed in 4.11
- Fix · CNA Linux (Linux) Fixed in 6.1.191, 6.6.160, 6.12.94, 6.18.17, 6.19.7, 7.0
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
Not affected: 1 product
- Red Hat Enterprise Linux 7
Timeline
- 2026-10-02 Threatist record created from CVE-2026-23247
- 2026-10-03 Alias added: GHSA-4hcm-qg7j-cc3v
- 2026-10-21 Fix available: Linux/[email protected], Linux/Linux@e873e8c16b2fb743a381a9e59c108e63512301ec · CNA
- 2026-10-21 1 new reference · CNA
- 2026-10-30 Fix available: Linux/Linux@025f532d8c5cfac77845e50daab7f478b360f2ac, Linux/[email protected] · CNA
- 2026-10-30 1 new reference · CNA
- 2026-11-05 CISA SSVC decision points changed
References
Patch 3
More Linux Kernel vulnerabilities
- 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
Sources
- CVE-2026-23247 · CVE Program
- CVE-2026-23247 · NVD
- FIRST EPSS
- GHSA-4hcm-qg7j-cc3v · GitHub Advisory Database · CC BY 4.0
- CVE-2026-23247 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences