Impact: Moderate Public Date: 2019-06-17 CWE: CWE-400 Bugzilla: 1719128: CVE-2019-11478 Kernel: tcp: excessive resource consumption while processing SACK blocks allows remote denial of service An excessive resource consumption flaw was found in the way the Linux kernel's networking subsystem processed TCP Selective Acknowledgment (SACK) segments. While processing SACK segments, the Linux kernel's socket buffer (SKB) data structure becomes fragmented, which leads to increased resource utilization to traverse and process these fragments as further SACK segments are received on the same TCP connection. A remote attacker could use this flaw to cause a denial of service (DoS) by sending a crafted sequence of SACK segments on a TCP connection.
Find out more about CVE-2019-11478 from the MITRE CVE dictionary dictionary and NIST NVD.
Red Hat Product Security is aware of this issue. Updates will be released as they become available. For additional information, please refer to the Red Hat Knowledgebase article: https://access.redhat.com/security/vulnerabilities/tcpsack
Red Hat Enterprise Linux 5 is now in Maintenance Support 2 Phase of maintenance life cycle. This has been rated as having Moderate security impact and is not currently planned to be addressed in future updates. For additional information, refer to the Red Hat Enterprise Linux Life Cycle: https://access.redhat.com/support/policy/updates/errata/.
NOTE: The following CVSS v3 metrics and score provided are preliminary and subject to review.
| CVSS3 Base Score | 5.3 |
|---|---|
| CVSS3 Base Metrics | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L |
| Attack Vector | Network |
| Attack Complexity | Low |
| Privileges Required | None |
| User Interaction | None |
| Scope | Unchanged |
| Confidentiality | None |
| Integrity Impact | None |
| Availability Impact | Low |
| Platform | Errata | Release Date |
|---|---|---|
| Red Hat Enterprise Linux Update Services for SAP Solutions 7.3 (kernel) | RHSA-2019:1484 | 2019-06-17 |
| Red Hat Enterprise Linux Extended Update Support 7.5 (kernel) | RHSA-2019:1482 | 2019-06-17 |
| Red Hat Enterprise Linux 8 (kernel) | RHSA-2019:1479 | 2019-06-17 |
| Red Hat Enterprise Linux Advanced Update Support 7.3 (kernel) | RHSA-2019:1484 | 2019-06-17 |
| Red Hat Enterprise Linux 7.3 Telco Extended Update Support (kernel) | RHSA-2019:1484 | 2019-06-17 |
| Red Hat Enterprise Linux Advanced Update Support 7.2 (kernel) | RHSA-2019:1485 | 2019-06-17 |
| Red Hat Enterprise Linux 8 (kernel) | RHSA-2019:1479 | 2019-06-17 |
| Red Hat Enterprise Linux 6 (kernel) | RHSA-2019:1488 | 2019-06-17 |
| Red Hat Enterprise Linux 7 (kernel) | RHSA-2019:1481 | 2019-06-17 |
| Red Hat Enterprise Linux Advanced Update Support 6.6 (kernel) | RHSA-2019:1489 | 2019-06-17 |
| Red Hat Enterprise Linux Extended Update Support 7.4 (kernel) | RHSA-2019:1483 | 2019-06-17 |
| Red Hat Enterprise Linux Server Update Services for SAP Solutions 7.2 (kernel) | RHSA-2019:1485 | 2019-06-17 |
| Red Hat Enterprise Linux Advanced Update Support 6.5 (kernel) | RHSA-2019:1490 | 2019-06-17 |
| Red Hat Enterprise Linux Server TUS (v. 7.2) (kernel) | RHSA-2019:1485 | 2019-06-17 |
| Platform | Package | State |
|---|---|---|
| Red Hat Virtualization 4 | redhat-virtualization-host | Affected |
| Red Hat OpenShift Container Platform 4.1 | kernel | Affected |
| Red Hat Enterprise MRG 2 | kernel-rt | Affected |
| Red Hat Enterprise Linux 8 | kernel-rt | Affected |
| Red Hat Enterprise Linux 7 | kernel-alt | Affected |
| Red Hat Enterprise Linux 7 | kernel-rt | Affected |
| Red Hat Enterprise Linux 5 | kernel | Out of support scope |
For mitigation, please refer to the Red Hat Knowledgebase article: https://access.redhat.com/security/vulnerabilities/tcpsack
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