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CVE-2019-11478

SACK can cause extensive memory use via fragmented resend queue

Public exploit available. Not confirmed exploited in the wild yet. A vendor fix is available.

CVSS 3.05.3MediumEPSS percentile99th95% chance in 30 daysCISA KEVNot listedNo confirmed exploitation
Public exploit: 6 sourcesFixVendor fixNo build named by the sources

Published Updated Sources: CVE.org, NVD, BDU, CSAF

NVD CVE.org

What to do

The vendor has published a fix. Version details are below where the sources state them.

Check it yourselfA free OpenVAS check exists for this CVE. Run it against your hosts.Is your organisation exposed?Request an assessment to establish which checks fit your systems.

What it is

From the CVE record

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.

In plain language

No plain-language summary for this CVE yet.

Exploitation

Where each signal puts this CVE on the scale from published to confirmed exploited.

EPSS99th
Public exploit
CISA KEV

Not in the catalog. CISA has not confirmed exploitation.

Public exploits

6 sources with a proof of concept or module.

Exploit links, PoCs and Metasploit modules after sign-in
EPSS

95% chance of exploitation activity in the next 30 days, which ranks it in the 99th percentile of scored CVEs.

Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.

Lifecycle

The patch came 471 days before any public exploit.

  1. OpenVAS check added
  2. EPSS band changemoderate → critical
  3. Public exploit / PoCsource: packetstorm
  4. Patch availableworkaround available, record updated
  5. Publishedweakness classified, att&ck mapped

Affected products

And 52 more affected products. See all after sign-in

Technical detail

CVSS 3.0 vector

Open in the CVSS calculator

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Scored 5.3 by NVD.

How it is reached

  • Attack Vector NetworkExploitable remotely over the network without any special conditions
  • Attack Complexity LowNo special conditions — the attack can be reliably reproduced
  • Privileges Required NoneNo authentication required — anyone can exploit this
  • User Interaction NoneNo user interaction needed — fully automated exploitation

Scope

  • Scope UnchangedImpact is limited to the vulnerable component itself

Impact if exploited

  • Confidentiality NoneNo confidentiality impact
  • Integrity NoneNo integrity impact
  • Availability LowReduced performance or intermittent disruption of service

Weaknesses

ATT&CK techniques

Mapped from the weaknesses above (CWE to ATT&CK), not observed in attacks.

Sources

References in the record

And 80 more references. See all after sign-in

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