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Main page Software Security Checklist Issue Handling Advisories Notes On Risk Advisory Template More


Title:       EGI SVG 'ALERT' [TLP:WHITE] Linux Kernel DOS vulnerability: TCP SACK panic CVE-2019-11477  

Date:        2019-06-20

Affected software and risk

Vulnerability concerning Linux Kernel

Package : Linux Kernel 
CVE ID  : CVE-2019-11477, CVE-2019-11478, CVE-2019-11479

Three related flaws were found in the Linux kernel's handling of TCP networking, which could allow a remote 
attacker to trigger a kernel panic in systems running the affected software and, as a result, impact the 
system's availability.  [R 1]

Actions required/recommended

Critical services should either be patched or mitigation should be applied. 

Component installation information

Sites running RedHat should see [R 2] 

Sites running Scientific Linux should see [R 3]

Sites running CentOS should see [R 4]

Sites running Ubuntu should see [R 5] 

Sites running Debian should see [R 6]


See [R 1] 

More information

At present SVG is not aware of any public exploits, or any cases where this has been exploited to compromise 
availability of services.  Therefore  we consider this to be less than 'High' risk at time of writing. 

RedHat considers this 'Important' due to the possibility of remote exploit.  

Normally, SVG only sends out advisories for issues assessed by SVG as 'High' or 'Critical' risk, but exceptions 
are made.  This is one of these cases, mainly because this flaw has been talked about in the press e.g. [R 7],
 and there is some risk to availability of services due to this issue.  


** WHITE information - Unlimited distribution 
  - see for distribution restrictions***                  


Minor updates may be made without re-distribution to the sites


Comments or questions should be sent to svg-rat  at

If you find or become aware of another vulnerability which is relevant to EGI you may report it by e-mail to  

report-vulnerability at
the EGI Software Vulnerability Group will take a look according to the procedure defined in [R 8]  

Note that this is undergoing revision to fully handle vulnerabilities in the EOSC-hub era. 


[R 1] 

[R 2] 

[R 3] 

[R 4] 

[R 5] Ubuntu  

[R 6] Debian  

[R 7]

[R 8]


SVG was alerted to this vulnerability by Vincent Brillault 

Yyyy-mm-dd  [EGI-SVG-2019-CVE-2019-11477] 

2019-06-18 SVG alerted to this issue by Vincent Brillault
2019-06-18 Acknowledgement from the EGI SVG to the reporter
2019-06-19 Not considered 'High' or 'Critical' risk
2019-06-19 Decided to send an Alert to site
2019-06-20 Alert sent to sites


This advisory has been prepared as part of the effort to fulfil EGI SVG's purpose 
"To minimize the risk to the EGI infrastructure arising from software vulnerabilities"

The risk is that assessed by the group, according to the EGI SVG issue handling procedure [R 8]  
in the context of how the software is used in the EGI infrastructure. It is the opinion of the group, 
we do not guarantee it to be correct. The risk may also be higher or lower in other deployments depending
 on how the software is used.   

Others may re-use this information provided they:-

1) Respect the provided TLP classification

2) Credit the EGI Software Vulnerability Group

Note that the SVG issue handling procedure is currently under review, to take account of the increasing 
inhomogeneity of the EGI infrastructure and the services in the EOSC-hub catalogue.

On behalf of the EGI SVG,