CVE-2015-3636: The ping_unhash function in net/ipv4/ping.c in the Linux kernel before 4.0.3 does not initialize a certain list data…

Is it exploited?

Reported, not confirmed by CISA. VulnCheck KEV lists it as exploited in the wild. CISA has not added it to its Known Exploited Vulnerabilities catalog as of 29 Oct 2026.

VulnCheck KEV lists it since 16 Jan 2018. It cites 1 public report, the first from 16 Jan 2018.

• securelist.com

How likely is exploitation in the next 30 days?

2.5%

EPSS score, percentile 84.5 of all scored records. A probability estimated by FIRST, not a report of exploitation.

How severe?

Not scored

The CVE record carries no CVSS score.

What should I do?

CISA has set no required action, because the vulnerability is not in KEV.

Advisories and patches (12)

Which versions are affected?

Not stated. The CVE record gives vendor and product as “n/a” and the version as “unspecified”.

Source: CISA KEV 2026.10.29, as of 29 Oct 2026; VulnCheck KEV, as of 30 Oct 2026; FIRST EPSS, as of 29 Oct 2026; CVE List, as of 30 Oct 2026. About the data.

Description

The ping_unhash function in net/ipv4/ping.c in the Linux kernel before 4.0.3 does not initialize a certain list data structure during an unhash operation, which allows local users to gain privileges or cause a denial of service (use-after-free and system crash) by leveraging the ability to make a SOCK_DGRAM socket system call for the IPPROTO_ICMP or IPPROTO_ICMPV6 protocol, and then making a connect system call after a disconnect.

Source: CVE List, as of 30 Oct 2026. About the data.

What to do

Advisories and patches

• DSA-3290 (Vendor advisory)
• USN-2631-1 (Vendor advisory)
• USN-2634-1 (Vendor advisory)
• SUSE-SU-2015:1491 (Vendor advisory)
• SUSE-SU-2015:1489 (Vendor advisory)
• USN-2632-1 (Vendor advisory)
• SUSE-SU-2015:1488 (Vendor advisory)
• FEDORA-2015-8518 (Vendor advisory)
• FEDORA-2015-7736 (Vendor advisory)
• RHSA-2015:1643 (Vendor advisory)
• openSUSE-SU-2015:1382 (Vendor advisory)
• SUSE-SU-2015:1478 (Vendor advisory)

This summary is based on the CVE record as of 30 Oct 2026. Check the vendor's advisory before you act: affected versions and fixes can change.

Affected products and versions

The CVE record does not name affected products or versions: vendor and product are “n/a” and the version is “unspecified”.

Source: CVE List, as of 30 Oct 2026. About the data.

Timeline