CVE-2019-11478
SACK can cause extensive memory use via fragmented resend queue
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Description
Jonathan Looney discovered that the TCP retransmission queue implementation in tcp_fragment in the Linux kernel could be fragmented when handling certain TCP Selective Acknowledgment (SACK) sequences. A remote attacker could use this to cause a denial of service. This has been fixed in stable kernel releases 4.4.182, 4.9.182, 4.14.127, 4.19.52, 5.1.11, and is fixed in commit f070ef2ac66716357066b683fb0baf55f8191a2e.
Official description from the CVE record, published by canonical. Copyright © 1999-2026 The MITRE Corporation. See /security/cve/legal for the CVE license. View the record on cve.org
Key data
CVSS 3.0 Medium 5.3
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Attack vector: Network
The vulnerable component can be reached over a network, possibly from the Internet.
Attack complexity: Low
No special conditions are needed. The attack can be repeated at will.
Privileges required: None
No account or privileges are needed.
User interaction: None
No action from any user is needed.
Scope: Unchanged
The impact stays within the vulnerable component.
Confidentiality impact: None
No effect on the secrecy of data.
Integrity impact: None
No effect on the trustworthiness of data.
Availability impact: Low
Limited effect on availability.
| Metric | Value | What it means |
|---|---|---|
| Attack vector | Network | The vulnerable component can be reached over a network, possibly from the Internet. |
| Attack complexity | Low | No special conditions are needed. The attack can be repeated at will. |
| Privileges required | None | No account or privileges are needed. |
| User interaction | None | No action from any user is needed. |
| Scope | Unchanged | The impact stays within the vulnerable component. |
| Confidentiality impact | None | No effect on the secrecy of data. |
| Integrity impact | None | No effect on the trustworthiness of data. |
| Availability impact | Low | Limited effect on availability. |
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EPSS
- Score
- 0.94414 (94.4% probability)
- Percentile
- 99.9%
- Scores of
- Nov 10, 2026
- Model
- v2026.06.15
Weakness (CWE)
- CWE-770Allocation of Resources Without Limits or Throttling
Affected products
Linux kernel
- affected: 4.4 up to before 4.4.182
- affected: 4.9 up to before 4.9.182
- affected: 4.14 up to before 4.14.127
- affected: 4.19 up to before 4.19.52
- affected: 5.1 up to before 5.1.11
References
- VU#905115 (kb.cert.org)third-party-advisory
- RHSA-2019:1594 (access.redhat.com)vendor-advisory
- RHSA-2019:1602 (access.redhat.com)vendor-advisory
- [oss-security] 20190628 Re: linux-distros membership application - Microsoft (openwall.com)mailing-list
- [oss-security] 20190706 Re: linux-distros membership application - Microsoft (openwall.com)mailing-list
- [oss-security] 20190706 Re: linux-distros membership application - Microsoft (openwall.com)mailing-list
- RHSA-2019:1699 (access.redhat.com)vendor-advisory
- 20190722 [SECURITY] [DSA 4484-1] linux security update (seclists.org)mailing-list
- [oss-security] 20191023 Membership application for linux-distros - VMware (openwall.com)mailing-list
- [oss-security] 20191029 Re: Membership application for linux-distros - VMware (openwall.com)mailing-list
- oracle.com/security-alerts/cpujan2020.html
- oracle.com/security-alerts/cpuoct2020.html
- github.com/Netflix/security-bulletins/blob/master/advisorie…
- wiki.ubuntu.com/SecurityTeam/KnowledgeBase/SACKPanic
- access.redhat.com/security/vulnerabilities/tcpsack
- packetstormsecurity.com/files/153346/Kernel-Live-Patch-Secu…
- kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA441…
- synology.com/security/advisory/Synology_SA_19_28
- security.netapp.com/advisory/ntap-20190625-0001
- kc.mcafee.com/corporate/index?page=content&id=SB10287
- vmware.com/security/advisories/VMSA-2019-0010.html
- cert-portal.siemens.com/productcert/pdf/ssa-462066.pdf
- us-cert.gov/ics/advisories/icsa-19-253-03
- packetstormsecurity.com/files/154951/Kernel-Live-Patch-Secu…
- arubanetworks.com/assets/alert/ARUBA-PSA-2020-010.txt
- git.kernel.org/pub/scm/linux/kernel/git/davem/net.git/commi…
- support.f5.com/csp/article/K26618426
- psirt.global.sonicwall.com/vuln-detail/SNWLID-2019-0007
- packetstormsecurity.com/files/154408/Kernel-Live-Patch-Secu…
Timeline
- ID reserved
- Record published
- Record last updated
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Data from the CVE Program (MITRE), CISA KEV and FIRST EPSS. CVSS is owned by FIRST and used by permission. Not affiliated with or endorsed by MITRE, CISA or FIRST. Data as of Nov 10, 2026, 19:50 UTC. Sources and licenses