CVE-2018-5391Linux Kernel Denial of Service
The Linux kernel, versions 3.9+, is vulnerable to a denial of service attack with low rates of specially modified packets targeting IP fragment re-assembly.
Published Sep 6, 2018 · Updated Aug 4, 2026 · Also known as DEBIAN-CVE-2018-5391, DSA-4272-1, SUSE-SU-2018:3792-1, SUSE-SU-2018:3860-1, SUSE-SU-2018:3881-1, SUSE-SU-2019:0645-1, SUSE-SU-2019:0672-1, UBUNTU-CVE-2018-5391
Key Facts
Patch immediately- CVE-2018-5391 is a high-severity vulnerability (CVSS 7.5 v3.1) affecting Big-Ip Access Policy Manager (F5), Big-Ip Advanced Firewall Manager (F5), Big-Ip Analytics (F5) and 22 more products.
- It is exploited in the wild, listed in Industry KEV feed since Feb 25, 2020. No public exploit code is known.
- EPSS estimates a 32% probability of exploitation in the next 30 days.
- Fixed versions are available, including bpftool 3.10.0-957.el7, cluster-md-kmp-default 4.12.14-25.13.1, cluster-md-kmp-default 4.4.121-92.92.1.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
Scores
CVSS v3.1
7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS (30-day exploit likelihood)
32%
Higher than 98.3% of all scored CVEs
Exploit maturity
Exploited (KEV)
ATLAS score
54/100
Publication score, see How it works
Exploitation Verdict
KEV listed
Feb 25, 2020
537 days after publication
Federal due date
None
No federal due date
Ransomware use
Not reported
Attributed actors
None named
Exploit & Defence Guidance
Exploit maturity
Exploited (KEV)
Public exploit code
0
Proof-of-concept links
In-the-wild evidence
5
Reports of active use
Advisories And Exploit References
- advisoryhttps://security-tracker.debian.org/tracker/CVE-2018-5391
- advisoryhttps://ubuntu.com/security/CVE-2018-5391
- advisoryhttps://www.cve.org/CVERecord?id=CVE-2018-5391
- advisoryRHSA-2018:2785
- advisoryRHSA-2018:2791
- advisoryRHSA-2018:2846
Description
The Linux kernel, versions 3.9+, is vulnerable to a denial of service attack with low rates of specially modified packets targeting IP fragment re-assembly. An attacker may cause a denial of service condition by sending specially crafted IP fragments.
Various vulnerabilities in IP fragmentation have been discovered and fixed over the years. The current vulnerability (CVE-2018-5391) became exploitable in the Linux kernel with the increase of the IP fragment reassembly queue size.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| Industry KEV feed | Feb 25, 2020 | n/a | Not reported |
Affected Products
615 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Big-Ip Access Policy ManagerF5 | See advisory | 11.6.5.1 |
| Big-Ip Advanced Firewall ManagerF5 | See advisory | 11.6.5.1 |
| Big-Ip AnalyticsF5 | See advisory | 11.6.5.1 |
| Big-Ip Application Acceleration ManagerF5 | See advisory | 11.6.5.1 |
| Big-Ip Application Security ManagerF5 | See advisory | 11.6.5.1 |
Patched Releases
bpftool
3.10.0-957.el7
cluster-md-kmp-default
4.12.14-25.13.1, 4.4.121-92.92.1, 4.4.175-94.79.1
cluster-md-kmp-rt
4.4.147-3.20.1
cluster-network-kmp-default
4.4.121-92.92.1
dlm-kmp-default
4.12.14-25.13.1, 4.4.121-92.92.1, 4.4.175-94.79.1
dlm-kmp-rt
4.4.147-3.20.1
Big-Ip Access Policy Manager
11.6.5.1
Big-Ip Advanced Firewall Manager
11.6.5.1
Big-Ip Analytics
11.6.5.1
Big-Ip Application Acceleration Manager
11.6.5.1
Big-Ip Application Security Manager
11.6.5.1
Big-Ip Domain Name System
11.6.5.1
Big-Ip Edge Gateway
11.6.5.1
Big-Ip Fraud Protection Service
11.6.5.1
Big-Ip Global Traffic Manager
11.6.5.1
Big-Ip Link Controller
11.6.5.1
Big-Ip Local Traffic Manager
11.6.5.1
Big-Ip Policy Enforcement Manager
11.6.5.1
Big-Ip Webaccelerator
11.6.5.1
gfs2-kmp-default
4.12.14-25.13.1, 4.4.121-92.92.1, 4.4.175-94.79.1
gfs2-kmp-rt
4.4.147-3.20.1
Kernel
0:2.6.32-754.6.3.el6, 0:3.10.0-957.el7, 2.6.32-754.6.3.el6, 3.10.0-957.el7, 4.14.62-65.117.amzn1, 4.14.62-70.117.amzn2, 3.9*
kernel-abi-whitelists
2.6.32-754.6.3.el6, 3.10.0-957.el7
kernel-alt
0:4.14.0-115.el7a
kernel-azure
4.12.14-5.13.1, 4.4.143-4.13.1
Timeline
Publicly disclosed
Sep 6, 2018
Added to Industry KEV feed
Feb 25, 2020
Last updated
Aug 4, 2026
Weakness Type
- CWE-20 Improper Input Validation
- CWE-400 Uncontrolled Resource Consumption
References
- advisorysecurity-tracker.debian.org · CVE-2018-5391
- advisoryubuntu.com · CVE-2018-5391
- advisorycve.org · CVERecord
- advisoryRHSA-2018:2785
- advisoryRHSA-2018:2791
FAQ
Common Questions.
The Linux kernel, versions 3.9+, is vulnerable to a denial of service attack with low rates of specially modified packets targeting IP fragment re-assembly.
Affected: Big-Ip Access Policy Manager (F5); Big-Ip Advanced Firewall Manager (F5); Big-Ip Analytics (F5), among others. The full list is in the CVE brief.
It is exploited in the wild, listed in Industry KEV feed since Feb 25, 2020.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
No public exploit code is known.
Fixed versions are available, including bpftool 3.10.0-957.el7, cluster-md-kmp-default 4.12.14-25.13.1, cluster-md-kmp-default 4.4.121-92.92.1.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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