SACK can cause extensive memory use via fragmented resend queue
CVE-2019-11478

7.5HIGH

Key Information:

Vendor

Linux
Status
Linux
Vendor
CVE Published:
19 June 2019

Badges

👾 Exploit Exists🟡 Public PoC🟣 EPSS 94%

What is CVE-2019-11478?

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.

Affected Version(s)

Linux kernel 4.4 < 4.4.182

Linux kernel 4.9 < 4.9.182

Linux kernel 4.14 < 4.14.127

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2019-11478
Created by jinjucat

References

https://www.kb.cert.org/vuls/id/905115
third-party-advisoryx_refsource_CERT-VN
https://access.redhat.com/errata/RHSA-2019:1594
vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2019:1602
vendor-advisoryx_refsource_REDHAT

EPSS Score

94% chance of being exploited in the next 30 days.

CVSS V3.1

Score:
7.5
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

CVSS V3.0

Score:
5.3
Severity:
MEDIUM
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

Jonathan Looney from Netflix
.