CVE-2019-11479

HIGHEPSS 100th pctl

7.5

CVSS v3

Description

Jonathan Looney discovered that the Linux kernel default MSS is hard-coded to 48 bytes. This allows a remote peer to fragment TCP resend queues significantly more than if a larger MSS were enforced. 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 commits 967c05aee439e6e5d7d805e195b3a20ef5c433d6 and 5f3e2bf008c2221478101ee72f5cb4654b9fc363.

CWE-405 CWE-770Allocation of Resources Without Limits or Throttling

How to fix

Remediation Available

kernelAmazon

Fixed in:0:4.14.123-111.109.amzn2

kernel-debuginfoAmazon

Fixed in:0:4.14.123-111.109.amzn2

kernel-debuginfo-common-aarch64Amazon

Fixed in:0:4.14.123-111.109.amzn2

kernel-debuginfo-common-x86_64Amazon

Fixed in:0:4.14.123-111.109.amzn2

kernel-develAmazon

Fixed in:0:4.14.123-111.109.amzn2

kernel-headersAmazon

Fixed in:0:4.14.123-111.109.amzn2

kernel-toolsAmazon

Fixed in:0:4.14.123-111.109.amzn2

kernel-tools-debuginfoAmazon

Fixed in:0:4.14.123-111.109.amzn2

kernel-tools-develAmazon

Fixed in:0:4.14.123-111.109.amzn2

perfAmazon

Fixed in:0:4.14.123-111.109.amzn2

perf-debuginfoAmazon

Fixed in:0:4.14.123-111.109.amzn2

python-perfAmazon

Fixed in:0:4.14.123-111.109.amzn2

python-perf-debuginfoAmazon

Fixed in:0:4.14.123-111.109.amzn2

linuxDebian

Fixed in:4.19.37-4CVE-2019-11479

linuxUbuntu

Fixed in:4.4.0-154.181USN-4041-1

This Ubuntu release reached end-of-life on 2021-04-02.

Fixed in:4.15.0-54.58USN-4041-1

This Ubuntu release reached end-of-life on 2023-05-31. Extended security maintenance is available until 2028-04-01.

linux-awsUbuntu

Fixed in:4.4.0-1048.52USN-4041-2

This Ubuntu release reached end-of-life on 2019-04-02.

Fixed in:4.4.0-1087.98USN-4041-1

This Ubuntu release reached end-of-life on 2021-04-02.

Fixed in:4.15.0-1043.45USN-4041-1

This Ubuntu release reached end-of-life on 2023-05-31. Extended security maintenance is available until 2028-04-01.

linux-aws-hweUbuntu

Fixed in:4.15.0-1043.45~16.04.1USN-4041-1

This Ubuntu release reached end-of-life on 2021-04-02.

linux-azureUbuntu

Fixed in:4.15.0-1049.54~14.04.1USN-4041-2

This Ubuntu release reached end-of-life on 2019-04-02.

Fixed in:4.15.0-1049.54USN-4041-1

This Ubuntu release reached end-of-life on 2021-04-02.

Fixed in:4.18.0-1023.24~18.04.1USN-4041-1

This Ubuntu release reached end-of-life on 2023-05-31. Extended security maintenance is available until 2028-04-01.

linux-gcpUbuntu

Fixed in:4.15.0-1036.38~16.04.1USN-4041-1

This Ubuntu release reached end-of-life on 2021-04-02.

Fixed in:4.15.0-1036.38USN-4041-1

This Ubuntu release reached end-of-life on 2023-05-31. Extended security maintenance is available until 2028-04-01.

linux-gke-4.15Ubuntu

Fixed in:4.15.0-1036.38USN-4041-1

This Ubuntu release reached end-of-life on 2023-05-31. Extended security maintenance is available until 2028-04-01.

linux-hweUbuntu

Fixed in:4.15.0-54.58~16.04.1USN-4041-1

This Ubuntu release reached end-of-life on 2021-04-02.

Fixed in:4.18.0-25.26~18.04.1USN-4041-1

This Ubuntu release reached end-of-life on 2023-05-31. Extended security maintenance is available until 2028-04-01.

linux-image-4.15.0-1017-oracleUbuntu

Fixed in:4.15.0-1017.19~16.04.2USN-4041-1

This Ubuntu release reached end-of-life on 2021-04-02.

Fixed in:4.15.0-1017.19USN-4041-1

This Ubuntu release reached end-of-life on 2023-05-31. Extended security maintenance is available until 2028-04-01.

linux-image-4.15.0-1036-gcpUbuntu

Fixed in:4.15.0-1036.38~16.04.1USN-4041-1

This Ubuntu release reached end-of-life on 2021-04-02.

Fixed in:4.15.0-1036.38USN-4041-1

This Ubuntu release reached end-of-life on 2023-05-31. Extended security maintenance is available until 2028-04-01.

linux-image-4.15.0-1036-gkeUbuntu

Fixed in:4.15.0-1036.38USN-4041-1

This Ubuntu release reached end-of-life on 2023-05-31. Extended security maintenance is available until 2028-04-01.

linux-image-4.15.0-1038-kvmUbuntu

Fixed in:4.15.0-1038.38USN-4041-1

This Ubuntu release reached end-of-life on 2023-05-31. Extended security maintenance is available until 2028-04-01.

linux-image-4.15.0-1040-raspi2Ubuntu

Fixed in:4.15.0-1040.43USN-4041-1

This Ubuntu release reached end-of-life on 2023-05-31. Extended security maintenance is available until 2028-04-01.

linux-image-4.15.0-1043-awsUbuntu

Fixed in:4.15.0-1043.45~16.04.1USN-4041-1

This Ubuntu release reached end-of-life on 2021-04-02.

Fixed in:4.15.0-1043.45USN-4041-1

This Ubuntu release reached end-of-life on 2023-05-31. Extended security maintenance is available until 2028-04-01.

linux-image-4.15.0-1045-oemUbuntu

Fixed in:4.15.0-1045.50USN-4041-1

This Ubuntu release reached end-of-life on 2023-05-31. Extended security maintenance is available until 2028-04-01.

linux-image-4.15.0-1049-azureUbuntu

Fixed in:4.15.0-1049.54USN-4041-1

This Ubuntu release reached end-of-life on 2021-04-02.

linux-image-4.15.0-1057-snapdragonUbuntu

Fixed in:4.15.0-1057.62USN-4041-1

This Ubuntu release reached end-of-life on 2023-05-31. Extended security maintenance is available until 2028-04-01.

This vulnerability affects an unusually large number of packages. The highest-confidence fixes are shown above; the full list is longer. Check the referenced advisories for complete coverage.

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploit Intelligence

91.66%probability of exploitation in 30 days

100thpercentile

Very high risk: more likely to be exploited than 100% of all known CVEs.

References

Related Vulnerabilities

Other CWE-405 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2024-11187	High	7.5	17%	-	Fix
CVE-2025-8677	High	7.5	11%	-	Fix
CVE-2021-38447	High	8.6	2.1%	-	Fix
CVE-2021-21359	Medium	5.9	1.7%	-	Fix
CVE-2018-15492	High	7.5	1.2%	-	-
CVE-2026-47774	High	7.5	1.0%	-	Fix

Common questions

How do I fix CVE-2019-11479?

Published advisories record a fix for 83 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.

Is CVE-2019-11479 being actively exploited?

Not that we know of. CVE-2019-11479 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 91.7% is the estimated probability that it will be exploited in the next 30 days. That is higher than 100% of all scored CVEs.

How severe is CVE-2019-11479?

CVE-2019-11479 has a CVSS v3 base score of 7.5, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2019-11479 affect?

Published advisories record a fix for kernel (Amazon), kernel-debuginfo (Amazon), kernel-debuginfo-common-aarch64 (Amazon), kernel-debuginfo-common-x86_64 (Amazon), and 79 more. Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-06-17.