How severe is CVE-2019-11479?

CVE-2019-11479 has a CVSS score of 7.5/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2019-11479?

Affected package information for CVE-2019-11479 is not yet fully mapped. Check the official advisory links for details.

How do I fix CVE-2019-11479?

No fixed version has been published for CVE-2019-11479 yet. Monitor the advisory for updates, apply mitigations recommended by the vendor, and use O3 Security to track when a fix becomes available in your stack.

Is CVE-2019-11479 actively exploited in the wild?

No public exploit code has been indexed for CVE-2019-11479 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2019-11479?

CVE-2019-11479 has an EPSS (Exploit Prediction Scoring System) score of 91.7%, placing it in the 100th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

What type of vulnerability is CVE-2019-11479?

CVE-2019-11479 is classified as CWE-405 (CWE-405), CWE-770 (CWE-770). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2019-11479 published, and has it been updated?

CVE-2019-11479 was published on June 19, 2019 and was last updated on April 16, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CVE-2019-11479: Denial of Service (High 7.5)

EPSS Exploitation Probability

via FIRST.org ↗

91.7%probability of exploitation in next 30 days

Very High Risk100th percentile+78.30%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

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.

Frequently Asked Questions

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.

O3 Security · Impact-Aware SCA

Is CVE-2019-11479 in your stack?

O3 detects CVE-2019-11479 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my stack How O3 SCA works